David Krause2.1 The model at a glance
| Stage | Question | Result | Chapter |
|---|---|---|---|
| I | Which costs were incurred? | cost-type plan with reconciled, chargeable costs | Ch. 4 |
| II | Where were they incurred? | cost center accounting sheet with surcharge rates and machine hour rates | Ch. 5–7 |
| III | What for were they incurred? | costing per order, quoted price, contribution margin | Ch. 10–13 |
2.2 Stage I — cost-type accounting
The starting point is the income statement. It is reconciled by subject matter (what belongs in cost accounting at all?) and by period (which share belongs in this period?). The result is a cost-type plan in which every item appears exactly once — cleaned of neutral expenses, supplemented with imputed costs.
2.3 Stage II — cost-center accounting
Direct costs can be assigned to the order directly. Overhead cannot — it is incurred for the whole company. The cost center accounting sheet distributes it across cost centers and derives the rates used for costing: surcharge rates in percent, machine hour rates in euros per hour.
Stage II is the most laborious and at the same time the most effective. Without it, only watering-can distribution remains — and with it the cross-subsidy between expensive and cheap cost centers that appears in Chapter 3 as error #07.
2.4 Stage III — cost-object accounting
Now what the whole thing was for is calculated: what does this part, this order, this assembly cost? The stage splits into pre-calculation (before the quote), concurrent calculation (during manufacturing) and post-calculation (after completion).
2.5 Which system fits which company?
| Company type | Recommended system | Reason |
|---|---|---|
| Job-shop, few machines | surcharge costing with one machine rate per bottleneck | keep effort low, but capture the expensive machine cleanly |
| CNC contract manufacturing, several processes | BAB with machine hour rates per cost center | processes differ by a multiple in their hour rate |
| Series production, one product | division costing | overhead distribution becomes trivial |
| Series production, variants | equivalence-number costing | variants differ proportionally |
2.6 The three dimensions: your individual system
Every cost accounting system can be classified along three dimensions. Their combination gives the system that fits company size, industry and steering ambition.
| Dimension | Variants | When which? |
|---|---|---|
| Time reference | actual · normal · planned | actual: entry, job-shop · normal: series · planned: controlling, budgets |
| Scope | full costs · partial costs (contribution) | full: pricing · partial: short-term decisions (Ch. 13) |
| Method | surcharge · machine hour rate · area-based | MHR for machine-bound work, surcharge for manual work |
2.7 System recommendation by industry
| Industry / process | Recommended system | Particularity |
|---|---|---|
| CNC machining (turning, milling, 5-axis) | actual × full × MHR | high machine diversity — MHR per cost center. Typically €25–65/h. |
| Plastic injection molding | actual × full × MHR | mold cost separate (special direct cost), energy substantial. €15–30/h. |
| Die casting (aluminium, zinc) | actual × full × MHR | rapid depreciation; shot unit cost as intermediate step. |
| Assembly / manual work | actual × full × area-based | no MHR — labor cost dominates, overhead surcharge on direct labor. |
| Contract manufacturer (mixed) | actual × full × MHR + area-based | MHR for machine stations, surcharge for assembly — a combination. |
Präzisionsteile Muster GmbH is a CNC contract manufacturer with around 30 employees, two turning centers, one 5-axis machining center and an assembly area. It therefore falls into the second row — BAB with machine hour rates. Every chapter works through this company.
