Chapter 11: Costing - Where Every Penny Goes |
11.1 The Mystery of the Disappearing Profit |
A mechanical factory had a problem. Their financial statements showed a healthy profit margin on paper. Their products were priced competitively. Their machines ran at high utilization. Their customers were satisfied. And yet, at the end of each year, the cash in the bank was consistently less than the profit reported. The owner was baffled. Where was the money going |
The answer, revealed after a painful investigation, was that the factory had no idea what their products actually cost. They had standard costs that were years out of date. They had no system to track variances between actual and standard. They allocated overhead using a simple percentage of direct labor, even though their direct labor content had been shrinking for a decade as automation increased. Some products that appeared profitable on paper were actually losing money. Other products that appeared marginal were actually highly profitable. The factory was making decisions based on fiction. |
This story is common. In mechanical manufacturing, where hundreds of different parts flow through dozens of operations, costing is enormously complex. A simple product like a machined bracket might consume raw material, machine time, tooling, labor, electricity, coolant, quality inspection, packaging, and shipping. Each of these elements has a cost. Some are direct and easy to trace. Others are indirect and must be allocated. Getting the allocation wrong leads to bad decisions, hidden losses, and disappearing profit. |
Costing is the ERP module that solves this mystery. It tracks where every penny goes, from the purchase of raw steel to the shipment of finished goods. It calculates product costs, tracks variances, allocates overhead, and provides the financial intelligence that managers need to price products, choose customers, and invest in improvements. This chapter explores how ERP systems do this, and why accurate costing is essential for any factory that wants to know what it is really earning. |
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11.2 The Building Blocks of Product Cost |
Every product in a mechanical factory has three fundamental cost components. The first is direct material cost - the cost of the raw materials and purchased components that go into the product. For a gearbox, the direct material cost includes the cast housing, the gears, the shafts, the bearings, the seals, and the fasteners. For a simple bracket, it includes the steel bar from which the bracket is machined, plus any purchased hardware like screws. |
Direct material cost is relatively straightforward to calculate. The ERP knows, from the bill of materials, how much of each material is required. The ERP also knows, from the purchasing module or from standard cost tables, the price of each material. Multiplying quantity by price gives the direct material cost. If the factory uses standard costing, the price is a predetermined standard. If the factory uses actual costing, the price is the actual purchase price of the specific lot used. |
The second component is direct labor cost - the cost of the workers who directly add value to the product. For a machined part, the direct labor includes the time the machinist spends setting up the machine, loading and unloading parts, and measuring finished parts. For an assembly, it includes the time the assembler spends fitting components, applying fasteners, and testing the finished product. |
Direct labor cost is also relatively straightforward. The ERP knows, from the routing, how many minutes of labor are required for each operation. The ERP also knows the labor rate for each worker or each job classification. Multiplying time by rate gives the direct labor cost. Again, the factory can use standard times and rates, or actual times from shop floor control. |
The third component is overhead - all the other costs that are necessary to run the factory but cannot be directly traced to a specific product. Overhead includes machine depreciation, electricity, factory rent, maintenance, supervision, quality assurance, material handling, and many other expenses. Overhead is the most difficult component to allocate, and the most common source of costing errors. |
The ERP calculates product cost by summing these three components for each operation, then summing across operations to get the total cost for the finished product. The result is a number that tells the factory, approximately, what it costs to make one unit. |
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11.3 Standard Costing Versus Actual Costing |
Every factory must choose between two fundamental approaches to costing: standard costing and actual costing. Both have advantages and disadvantages, and both are supported by modern ERP systems. |
Standard costing uses predetermined costs for materials, labor, and overhead. The standard material cost is based on expected purchase prices. The standard labor cost is based on expected labor rates and expected operation times. The standard overhead cost is based on expected overhead spending and expected production volume. The ERP calculates the standard cost of a product before it is made, using these standards. After the product is made, the ERP compares the actual costs to the standard costs. The differences are called variances. |
Standard costing has several advantages. It is predictable. Managers can estimate product costs before committing to production. It highlights problems. A large variance tells management that something is wrong - either the standard is wrong, or the factory performed poorly. It simplifies inventory valuation. Inventory is valued at standard cost, which is stable and does not fluctuate with every purchase or every overtime shift. |
The disadvantage of standard costing is that standards become outdated. A standard material price set two years ago may be far from today's market price. A standard operation time based on an old machine may be irrelevant after a new machine is installed. If standards are not regularly updated, the cost information becomes misleading. |
Actual costing uses the real costs incurred. The actual material cost is the actual purchase price of the specific lot used. The actual labor cost is the actual labor time multiplied by the actual labor rate, including overtime premiums. The actual overhead cost is allocated based on actual overhead spending and actual production volume. The ERP calculates product cost after the product is made, using these actuals. |
Actual costing has the advantage of accuracy. The reported cost is what the factory actually spent. There are no variances to explain. The disadvantage is that actual costs are not known until after production is complete. Managers cannot use actual costs to make decisions about pricing or product mix before production. Also, actual costs can be volatile. A single expensive purchase or a single machine breakdown can dramatically affect the cost of products made during that period. |
Most mechanical factories use standard costing for routine management and inventory valuation, while also tracking actual costs for analysis. The ERP supports both, allowing managers to see standard costs for planning and actual costs for learning. |
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11.4 Direct Material Cost - Tracking Every Pound |
Direct material cost seems simple, but in a busy factory with thousands of material movements, it is surprisingly complex. The ERP must track not only how much material was issued to a work order, but also which specific lot was issued, at what price. |
When a worker issues material to a work order, they scan the material's lot number and the work order number. The ERP retrieves the cost of that specific lot. For purchased materials, the cost is the purchase price from the supplier's invoice. For manufactured components, the cost is the cost calculated for that component when it was produced. The ERP then adds the material cost to the work order's cumulative cost. |
If the factory uses standard costing, the ERP also records a material price variance. This is the difference between the standard material cost and the actual purchase price. A positive variance (actual higher than standard) indicates that purchasing paid more than expected. A negative variance (actual lower than standard) indicates that purchasing paid less. The variance is reported separately, so management can see whether cost overruns are due to purchasing or to production. |
The ERP also tracks material usage variance. This is the difference between the standard quantity of material required for the work order and the actual quantity issued. If the standard says a bracket requires one kilogram of steel, but the work order actually consumed 1.1 kilograms, the ERP records a usage variance. The variance might be due to scrap, to a defective raw material, or to an incorrect standard. The ERP cannot explain the cause, but it can flag the existence of the variance for investigation. |
Accurate material costing depends on accurate material tracking. If workers issue material without recording it, the work order will show lower material cost than actual. If workers record material issues for the wrong work order, costs will be misallocated. The ERP provides the tools for accurate tracking, but the discipline to use them must come from the shop floor. |
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11.5 Direct Labor Cost - Capturing Every Minute |
Direct labor cost is similarly complex. The ERP must track not only how much time each worker spent on each work order, but also the worker's labor rate, including overtime and shift differentials. |
When a worker starts an operation, they scan the work order or enter their start time. When they complete the operation, they scan again or enter their end time. The ERP calculates the elapsed time. It multiplies that time by the worker's labor rate, which is stored in the human resources module. The result is the direct labor cost for that operation. |
If the factory uses standard costing, the ERP also records a labor rate variance and a labor efficiency variance. The rate variance is the difference between the standard labor rate and the actual labor rate. If overtime or a higher-skilled worker was used, the actual rate may be higher than standard. The efficiency variance is the difference between the standard time for the operation and the actual time. If the worker took longer than standard, perhaps because of a difficult setup or a poorly designed process, the efficiency variance is positive. |
Labor efficiency variance is one of the most valuable metrics in mechanical manufacturing. A consistently positive efficiency variance on a particular operation suggests that the standard is too optimistic, or that the process needs improvement. A consistently negative variance suggests that the standard is too pessimistic, or that the operator is exceptionally skilled. The ERP cannot make these judgments, but it provides the data for them. |
Accurate labor costing depends on accurate time tracking. If workers forget to record their start and end times, or if they record times for the wrong work orders, the labor cost information is corrupted. Again, discipline is essential. The best factories make time tracking as easy as possible, with barcode scanners or touchscreens at every work center, and they build time tracking into the standard work routine. |
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11.6 Overhead Allocation - The Art of Fair Distribution |
Overhead is the most challenging cost component. Unlike direct material and direct labor, overhead cannot be traced directly to a specific product. The electricity that powers the factory lights every product equally. The maintenance department's salary supports every machine. The plant manager's time is spent on every order. Some method is needed to allocate these indirect costs to products. |
The simplest method, and the one used by many small factories, is to allocate overhead based on direct labor hours or direct labor cost. The logic is that products that require more labor also consume more overhead. This method was reasonable when labor was the dominant cost in manufacturing. But in modern mechanical factories, with expensive automated machines, labor is often a small fraction of total cost. A product that runs on a costly CNC machine for many hours but requires little labor will be under-costed by a labor-based allocation. A product that requires much labor but runs on cheap manual machines will be over-costed. |
A better method is activity-based costing (ABC) . ABC recognizes that different products consume different types of overhead in different proportions. Instead of a single overhead pool and a single allocation base, ABC uses multiple pools and multiple allocation bases. |
For example, machine-related overhead - depreciation, maintenance, electricity - is allocated based on machine hours. A product that uses a costly machine for many hours receives a large share of machine overhead. Set-up-related overhead - the cost of setup labor, tooling, and engineering support - is allocated based on the number of setups. A product that is produced in small batches with frequent setups receives a large share of setup overhead. Material-handling overhead is allocated based on the number of material moves or the weight of the material. |
The ERP supports activity-based costing by allowing the factory to define multiple cost pools and multiple allocation bases. The system collects data on each allocation base - machine hours from shop floor control, number of setups from work orders, material moves from inventory transactions - and uses that data to allocate overhead to products. The result is a much more accurate product cost than a simple labor-based allocation. |
The trade-off is complexity. Activity-based costing requires more data and more analysis than simple allocation. Many factories start with a simple method and add complexity only where it matters - for products with very different cost structures, or for decisions where accuracy is critical. |
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11.7 Work-in-Progress Valuation - The Hidden Asset |
At any moment, a mechanical factory has significant value tied up in partially completed products. Raw steel has been cut but not yet machined. Shafts have been turned but not yet ground. Gearboxes have been assembled but not yet tested. This is work-in-progress (WIP) inventory. It is an asset on the balance sheet, and its valuation is important for financial reporting. |
The ERP values WIP automatically. When a work order is released, the ERP assigns no value to it. As materials are issued, the ERP adds their cost to the work order's WIP balance. As labor and machine time are reported, the ERP adds their cost, including allocated overhead. As the work order progresses through operations, the WIP balance grows. When the work order is completed and the finished product is moved to finished goods inventory, the ERP moves the full cost from WIP to finished goods. |
If a work order is partially complete at the end of a financial period, the ERP must estimate the value of the incomplete portion. This is done using the percentage of completion method. The ERP knows which operations have been completed and which are still open. It sums the costs of the completed operations and adds an estimate of the costs incurred for the in-progress operation. The result is a reasonable approximation of the WIP value. |
Accurate WIP valuation depends on accurate reporting of material issues, labor time, and operation completion. If workers consistently fail to report the completion of an operation, the ERP will understate WIP value. If they report completion prematurely, the ERP will overstate WIP value. The periodic physical inventory of WIP - counting and valuing the partially completed parts on the shop floor - provides a check on the ERP's calculations. |
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11.8 Variances - The Signal in the Noise |
Variances are not just accounting artifacts. They are signals that something has changed. A large variance deserves investigation. A small variance can be ignored. The ERP's job is to calculate variances accurately and present them in a useful way. |
There are many types of variances, but a few are most important for mechanical manufacturing. Material price variance signals changes in the purchasing environment or in purchasing performance. A large positive material price variance on a particular item might indicate that the supplier has raised prices, or that the buyer failed to negotiate effectively. |
Material usage variance signals inefficiency in production. A large positive usage variance on a particular operation might indicate that the machine is producing excess scrap, that the raw material is of poor quality, or that the operator is making errors. The ERP cannot tell which, but it can direct attention to the operation. |
Labor rate variance signals changes in workforce composition or overtime. A large positive labor rate variance might indicate that the factory is using more overtime than planned, or that higher-skilled workers are being used for jobs that could be done by lower-skilled workers. |
Labor efficiency variance signals productivity changes. A large positive efficiency variance might indicate that the standard times are too optimistic, that the machine is slow, or that the operator is inexperienced. A large negative variance might indicate that the standard times are too pessimistic, that a new tool has improved speed, or that the operator is exceptionally skilled. |
Overhead spending variance signals changes in overhead costs. A large positive spending variance might indicate that electricity prices have risen, that maintenance costs are higher than expected, or that the factory is spending more on supervision. |
Overhead volume variance signals changes in production volume. If the factory produces less than planned, the fixed overhead is spread over fewer units, causing a positive volume variance. If it produces more than planned, the variance is negative. The volume variance is not a sign of inefficiency; it is a sign that the factory's volume is different from the volume used to set the overhead rates. |
The ERP presents these variances in reports, often color-coded by significance. A small variance might be shown in green, indicating it can be ignored. A large variance in red requires investigation. The production manager, the purchasing manager, and the cost accountant review the variances each month, investigate the causes, and take corrective action. |
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11.9 Marginal Costing for Decision Making |
Standard costing and actual costing are useful for financial reporting and for understanding the full cost of a product. But for certain decisions, a different approach is needed: marginal costing, also known as direct costing. |
Marginal costing separates costs into fixed costs and variable costs. Variable costs change with the volume of production - direct material, direct labor, and variable overhead like electricity. Fixed costs do not change with volume - factory rent, depreciation on buildings, salaries of managers. In marginal costing, only variable costs are assigned to products. Fixed costs are treated as period costs, deducted in total from the contribution margin. |
Marginal costing is valuable for short-term decisions. When a factory has spare capacity and a customer offers a low price for a large order, the decision should be based on marginal cost. If the price covers the variable costs and makes some contribution to fixed costs, the order is profitable in the short term. Using full cost would reject the order, leaving capacity idle. |
The ERP can support marginal costing by tracking which costs are variable and which are fixed. The same data used for full costing can be reclassified for marginal analysis. The manager can see, for each product, the contribution margin - the difference between selling price and variable cost. Products with high contribution margins are candidates for increased volume. Products with low or negative contribution margins need review. |
Marginal costing is not a replacement for full costing. Full costing is required for financial reporting. Marginal costing is a tool for specific decisions. The ERP provides both, and the manager must choose the right tool for the question at hand. |
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11.10 Real-World Example: The Job Shop's Costing Revelation |
Consider a job shop that makes custom machined parts for a variety of industries. The shop had hundreds of customers, thousands of part numbers, and a simple costing method: direct material plus direct labor at a standard rate, plus overhead at one hundred percent of direct labor. The owner believed that if the shop covered its direct costs and the overhead markup, it was making money. |
The shop implemented an ERP with full costing capabilities, including activity-based overhead allocation. The first run of the new costing system was a shock. Some parts that the owner thought were highly profitable were actually losing money. Other parts that were considered marginal were highly profitable. The discrepancy was caused by the overhead allocation. The labor-based method had over-costed parts that required little machine time but much labor, and under-costed parts that required much machine time but little labor. |
For example, a simple bracket that required ten minutes of labor on a manual mill but no CNC time was assigned ten dollars of overhead (one hundred percent of labor). The actual overhead consumed by that part, under activity-based costing, was about twelve dollars - close enough. But a complex aerospace part that required five minutes of labor but sixty minutes on an expensive five-axis CNC machine was also assigned five dollars of overhead under the old method. The actual overhead consumed by the CNC machine - depreciation, maintenance, electricity - was fifty dollars. The part was being under-costed by forty-five dollars. The shop had been selling complex CNC work at prices that did not cover the true cost. |
The owner used the new cost information to revise pricing. Prices for simple manual work were reduced slightly, making the shop more competitive. Prices for complex CNC work were increased significantly, bringing them in line with true costs. Some customers complained, but most accepted the new prices when shown the data (in general terms). The shop's profit margin increased by eight percentage points in the first year. The owner later said that the ERP's costing module was the single most valuable part of the entire system. |
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11.11 The Human Factor - Costing as a Management Discipline |
Costing is not just an accounting exercise. It is a management discipline. The numbers are only useful if managers act on them. A factory that calculates variances but ignores them will see no improvement. A factory that allocates overhead precisely but uses the resulting costs to justify bad decisions will see no benefit. |
The ERP provides the data. The managers must provide the judgment. When a material usage variance appears, the production manager must investigate. Is the machine producing scrapIs the operator making errorsIs the standard wrongThe investigation leads to action: a maintenance adjustment, additional training, or a standard update. |
When an overhead spending variance appears, the plant manager must investigate. Is the maintenance budget being exceededAre electricity costs risingIs there waste that can be eliminatedThe investigation leads to action: a new maintenance contract, an energy efficiency project, or a process change. |
When a product's full cost is higher than its selling price, the general manager must decide. Can the price be raisedCan the cost be reducedShould the product be discontinuedThese are hard decisions, but they are better made with accurate cost information than without it. |
The most successful factories treat costing as a continuous improvement tool, not a periodic compliance exercise. They review variances weekly, not monthly. They update standards whenever processes change. They involve operators in understanding costs, because the people on the shop floor often have the best ideas for cost reduction. |
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11.12 Summary: Knowing What You Really Earn |
The mystery of the disappearing profit is not a mystery when you have accurate costing. The money is not disappearing. It was never there. The factory was making decisions based on fictional costs, accepting orders that lost money, rejecting orders that were profitable, and wondering why the bank balance did not match the profit and loss statement. |
Costing is the ERP module that reveals the truth. It tracks direct material, direct labor, and overhead. It allocates overhead fairly using activity-based methods. It calculates variances that signal problems and opportunities. It values work-in-progress accurately for financial reporting. It supports marginal costing for short-term decisions. And it provides the financial intelligence that managers need to run a profitable factory. |
But costing is not a set-it-and-forget-it module. It requires discipline. Standards must be updated. Variances must be investigated. Overhead allocations must be reviewed. The data from shop floor control, purchasing, and inventory must be accurate. When these disciplines are in place, costing becomes a strategic weapon. The factory knows what it really earns. And with that knowledge, it can price confidently, invest wisely, and grow profitably. |
In the next chapter, we will explore how the ERP manages the human side of the factory - the skills, training, and schedules of the people who make everything possible. Labor is not just a cost to be allocated. It is a resource to be developed. And the ERP has powerful tools for that development. |
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Key takeaways from Chapter 11: |
1. Product cost has three components: direct material, direct labor, and overhead - overhead is the hardest to allocate accurately. |
2. Standard costing uses predetermined costs and tracks variances; actual costing uses real costs but is not known until after production. |
3. Material costing tracks both price variance (difference between standard and actual purchase price) and usage variance (difference between standard and actual quantity consumed). |
4. Labor costing tracks both rate variance (difference between standard and actual labor rate) and efficiency variance (difference between standard and actual time). |
5. Overhead allocation is the most challenging - activity-based costing (ABC) uses multiple cost pools and allocation bases for greater accuracy. |
6. Work-in-progress (WIP) valuation captures the value of partially completed products, growing as materials, labor, and overhead are added. |
7. Variances are signals, not problems themselves - they direct attention to areas that need investigation and improvement. |
8. Marginal costing separates fixed and variable costs, supporting short-term decisions about pricing and order acceptance. |
9. Real-world examples show that inaccurate costing leads to bad pricing and hidden losses; accurate costing transforms profitability. |
10. Costing is a management discipline, not just an accounting exercise - variances must be investigated, standards updated, and overhead allocations reviewed regularly. |
11. The ERP provides the data; managers provide the judgment - the combination drives continuous improvement in cost performance. |
cs@easiersoft.com