Integral Logistics Management — Operations Management and Supply Chain Management Within and Across Companies

16.1.4 Cost Accumulation Breakdown: The Cost Breakdown Structure of a Product

Intended learning outcomes: Explain cost accumulation breakdown. Present in detail material costs, external and internal labor costs. Produce an overview on tooling costs and general fixed manufacturing costs. Differentiate between variable manufacturing costs and (full) manufacturing costs. Identify general and administrative expenses (G&A) and cost of sales. Describe value added.



The cost accumulation breakdown, or cost breakdown structure of a product, is the accumulation of manufacturing costs in various subdivisions of costs, or cost types, according to the product structure.

Figure 16.1.4.1 shows an example cost accumulation breakdown for calculating the product costs. It is a break­down of costs used by a manufacturing company.

Fig. 16.1.4.1       Example cost accumulation structure, or cost breakdown structure of a product.

Material costs are the costs associated with purchased components.

Material costs are subdivided into two cost subtypes:

  • The variable material costs for a product are the sum of, firstly, the cost of purchased components (the true procurement costs), and, secondly, the variable material costs for all components produced in-house.

    Note: In many American costing systems, material costs also include the full cost of goods manufactured for components produced in-house (variable and fixed), rather than just the variable material costs (principle of the make-or-buy decision). In that case, the term component costs would be more appropriate than material costs (see the definition of the terms material and components in Section 1.1.1.
  • The fixed material costs comprise, firstly, the costs of supplier and component qualification, secondly, the purchasing costs, thirdly, the carrying costs, and fourthly, the costs of receiving and inspecting purchased goods.

    The simplest way to express fixed material costs is as a percentage by dividing the total fixed costs by the total turnover of goods with variable costs. This calculation is carried out at the end of a budget period, using the data for the period just ended. It serves as the forecast for the next period. It is possible to use different percentages as a function of the storage type (special packa­ging or buildings, refrigerators, etc.) or as a function of the type or value of the goods (such as iron, gold, wood). How­ever, the fixed costs must then be recorded separately for the various categories. The more exact and “fairly” costs should be allocated to products, the more expensive costing becomes. This also holds for activity-based costing (Section 16.4).
External labor costs are the costs associated with the subcontracting of work.

Work may be subcontracted because the necessary production techniques, infrastructure (special machines), or capacity are not available in-house. For financial accounting, special cost centers are defined for such operations. The ID used for the cost center may be the same as the supplier identification. External labor costs are further subdivided into two subtypes:

  • Variable external labor costsare the sum of all invoices arising from work subcontracted to suppliers, and they contain the suppliers’ fixed costs. For the subcontracting company, on the other hand, these costs are variable costs.
  • Fixed external labor costs are the various costs generated by the subcontracting of work, particularly cost of shipping and transporting goods to and from the supplier, cost of receiving and inspecting the goods processed by subcontractors, as well as administra­tive expenses associated with subcontracting work (evaluation, writing the order, and so on).

    Usually, fixed external costs are expressed as a percentage in relation to the total in­voiced amount for subcontracted work. We can apply different percentages to different categories of suppliers, in which case the fixed costs must be recorded separately for each category. As with material costs, the percentages are calculated at the end of a budget period and then serve as forecasts for the next budget period.
Internal labor costs are the sum of the costs for all in-house operations to manufacture the product.

Every internal operation is assigned to a work center,[note 1601] for which two cost rates are established. A cost rate is related to a capacity unit, that is, the unit of measure of the capacity for a work center (mostly an hour).

  • The cost rate for variable internal labor costs.This includes the costs for wages, plant utilities, plant supplies used, and so on that are needed to carry out the operation. The cost rate is essentially determined either directly or by measurement.
  • The cost rate for fixed internal labor costs. This includes the depreciation costs for both machinery and infrastructure and tools and devices, provided that tools and devices are not depreciated independently of the machinery. It also includes ongoing costs, such as operations management. The cost rate is always calcula­ted at the end of a budget period and is used as the forecast for the next period. The total fixed costs are then divided by the forecast load quantity for the next budget period.

The variable and fixed costs of an operation are calculated by multiplying the standard load of an operation (see Figure 13.1.2.2) by the cost rate for variable or fixed costs.

The tooling costs for an operation are the costs incurred by the use of tools during that operation.

In the past, tooling costs were regarded as part of the fixed costs for a capacity unit. Today, they represent such a large proportion of the costs and often differ so widely for each manufactured product that it is more sensible to set them out separately. The following technique, which accords with the activity-based costing approach (see Section 16.4), provides an illustration:

  • The tooling costs per operation are calculated by multiplying the batch size by the cost rate per tool use, which is part of the master data for the tool (see also Section 17.2.7). We calculate the cost rate per tool use by dividing the amount to be depreciated by the expected number of uses of the tool.
  • The actual number of uses of the tool (a cost driver) is recorded by the shop floor data collection system during the operation in question and is then stored in the master and inventory data for the tool. We can thus compare the actual number of uses against the budgeted number of uses for the tool. The cost rate can then be adjusted depending on the results of the comparison.
The general fixed manufacturing costs are the (fixed) costs for
everything not associated directly with the manufacturing process or production infrastructure.

Typical general fixed manufacturing costs include licenses as well as general planning & control, manufacturing process design, and head of production.

These are usually calculated using one or more percentages that relate to the sum of these costs. The sum of all of the general fixed manufacturing costs is divided by the full cost of goods manufactured mentioned above. Again, this calculation takes place at the end of a budget period and serves as the basis for the forecast for the next period.

Variable manufacturing costs is the sum of all the variable costs (material and labor) of a specific product.

(Full) manufacturing costs, also called cost of goods sold, is the sum of all the variable and fixed costs (lab­or, material, and overhead) of a specific product or for a given period of time.

In addition to the fixed costs mentioned above, there are also:

General and administrative expenses (G&A) are the sum of (fixed) costs for R&D, administration, marketing and sales, and general management.

G&A are expressed as a percentage in relation to the (full) cost of goods sold. This percentage is calculated by dividing the accumulated G&A by the full cost of goods sold during the budget period, again at the end of the budget period. The result is used as the basis for the forecast for the next period.

The cost of sales is the sum of the costs of goods sold and the G&A for a specific product or for the products sold during a given period of time.

Finally, value-added is an organization’s own output.

The value added of a product is defined as the full cost of goods manufactured minus variable material costs, minus variable external production costs, minus a part of the general fixed manufacturing costs (such as licenses). [note 1602]

The complement of value-added are purchased products or services. This definition of added value also serves as the basis for some aspects of taxation.

The variable costs of goods manufactured serve as the short-term lower limit for the sales price (variable, costing) or partial costing, while the full cost of goods manufactured can be regarded as the medium-term lower limit for the sales price (full costing, absorption costing). The sales price then — ideally — includes a profit margin in addition to the cost of sales. For complete costing, costs must be broken down into all eight cost types for each item. The full manufacturing costs can then be derived simply by adding the cost types together.




Course section 16.1: Subsections and their intended learning outcomes

  • 16.1.4 Cost Accumulation Breakdown: The Cost Breakdown Structure of a Product

    Intended learning outcomes: Explain cost accumulation breakdown. Present in detail material costs, external and internal labor costs. Produce an overview on tooling costs and general fixed manufacturing costs. Differentiate between variable manufacturing costs and (full) manufacturing costs. Identify general and administrative expenses (G&A) and cost of sales. Describe value added.