Missing a Line on the Quotation Means Paying for the Customer — Four Types of Quality Cost Allocation Benchmarks and Calculation Examples
In the quotation meeting room, the cost sheet is typically laid out as follows: materials, labor, manufacturing overhead, administrative expenses, and target gross profit. After adding these five lines, a price is generated. Where is the quality cost? Most companies cannot answer this question—it is blended into manufacturing overhead and administrative expenses, allocated to all products and all customers at a uniform percentage.
This is where the problem lies: one customer has a PPM target of 50, with penalties for exceeding the target, and quarterly on-site screening; another customer has no penalties and only requires batch sampling inspection. Using the same percentage to allocate quality costs means that the customer with lower requirements is paying for the customer with higher requirements, and it also hides the true cost of the higher-requirement customer. Once the price is signed, the loss can only be found in the gross profit.
1. Missing Costs Are Not Just a Line, but a Pricing Basis
Among the four types of quality costs, prevention and appraisal are "costs to avoid errors," while internal and external failures are "costs incurred due to errors." The first two are often calculated as fixed manufacturing costs during quotation, while the latter two are almost never included in the quotation sheet—because they are recorded by the quality department, manufacturing department, or as extraordinary expenses, and the quotation is prepared by sales and finance.
The consequences are straightforward: the quotation reflects the "costs when production goes smoothly," not the "actual costs for this customer and this product." For the same part sold to different customers, the quality cost can differ by 3 to 5 yuan per piece, but the quotation often only differs by a few tenths of a yuan.
To add this line back, there is no need to rebuild the cost system; just follow these three steps: translate customer terms into cost items, set allocation benchmarks for each type, and apply the allocation amount to the quotation line.
2. Step One: Translate Customer Terms into Allocable Risk Items
Review the customer's quality agreement, procurement contract, and technical agreement. Any place with "requirements" and "consequences" can be translated into a cost item. The following eight items are common and can be used directly as a checklist:
| Customer Terms or Requirements | Corresponding Quality Cost Item | Allocation Basis |
|---|---|---|
| PPM target and penalty for exceeding | External failure (penalty) | Penalty per unit × estimated number of units exceeding |
| Screening, sorting, and rework at customer site | External failure | Historical screening frequency × cost per occurrence (including travel and downtime) |
| Warranty period, three guarantees, recall responsibility | External failure (warranty reserve) | Sales × allocation rate (determined by industry failure rate) |
| Return logistics and material loss | External failure | Return rate × cost per unit for logistics and loss |
| PPAP, DV/PV, material certification | Appraisal cost (one-time) | Total project cost ÷ lifecycle supply volume |
| Full inspection, specified inspection tools, third-party reports | Appraisal cost | Inspection time per unit × labor rate + report fee |
| Special packaging, rust prevention, labeling, traceability | Prevention cost | Additional packaging material and labor time per unit |
| Second-party audit, system maintenance, on-site quality representative | Prevention cost | Annual cost ÷ annual supply volume |
The purpose of this table is not to calculate accurately, but to ensure no items are missed. It is common for companies to have more than three of these eight items not included in their quotation sheets, with the most frequently missed being screening costs at the customer site and one-time PPAP costs.
3. Step Two: Allocation Benchmarks for Each Type of Cost
The role of allocation benchmarks is to provide a repeatable basis, avoiding the need to estimate each product anew. The following four bases are empirical ranges suitable for the first version; after one year, they should be replaced with actual data.
| Category | Allocation Base | Empirical Range | Key Points |
|---|---|---|---|
| Prevention | Sales | 0.3%～1.0% | Use the upper limit for new customers, new projects, or those with special characteristic requirements |
| Appraisal | Inspection labor quota | Per unit inspection minutes × labor rate | Full inspection and sampling inspection differ greatly; calculate based on the inspection plan, not sales |
| Internal failure | Historical nonconforming rate × disposition cost | Use actual values by product family | Rework and scrap costs differ; use weighted averages based on proportions |
| External failure | Customer terms and historical customer complaints | Allocate separately by customer | Do not use the plant-wide average nonconforming rate; differences in customer inspection strictness are the main cause |
Four iron rules: external failure must be allocated by customer; appraisal costs must be calculated based on the inspection plan; one-time project costs should be spread over the lifecycle, not the first year; prevention costs cannot be zero, as they are the only item that can reduce the other three.
4. Step Three: Calculation Example for a Part
A certain car bracket, with an annual supply of 120,000 pieces. Original quotation composition: materials 18.00 yuan, labor 5.50 yuan, manufacturing overhead 6.00 yuan, administrative expenses 3.00 yuan, totaling 32.50 yuan; target gross profit 10%, quotation 36.00 yuan, gross profit per unit 3.50 yuan.
Quality cost allocation based on customer terms:
- Prevention: Quotation × 0.5% = 0.18 yuan;
- Appraisal: Full air-tightness inspection 0.6 minutes + partial three-coordinate inspection 0.10, totaling 0.80 yuan;
- Internal failure: Nonconforming rate 1.8%, with 70% rework (4 yuan per unit) and 30% scrap (9 yuan per unit), allocation per unit 1.8% × (0.7 × 4 + 0.3 × 9) = 0.10 yuan;
- External failure: Customer screening twice a year, 45,000 yuan per occurrence, averaging 0.75 yuan per unit; warranty reserve 36.00 × 0.3% = 0.11 yuan, totaling 0.86 yuan.
The total of the four items is 1.94 yuan per unit. The full cost becomes 34.44 yuan, gross profit drops from 3.50 yuan to 1.56 yuan, and the gross profit margin falls from 9.7% to 4.3%.
Re-quoting based on full cost, the price should be around 37.90 yuan (34.44 × 1.10). This number is usually not accepted—customers will compare it to the old price. Therefore, a more practical approach is to choose one of the following: either have the customer bear the screening cost and change the PPM penalty to a commitment for rectification, thereby negotiating away the 0.86 yuan for external failure; or accept a lower price but simultaneously initiate an internal project to reduce the nonconforming rate from 1.8% to 0.6%, using the reduction in internal failure to recover the gross profit. The purpose of the quotation is not to calculate a high price, but to ensure that each price corresponds to a clear set of quality conditions.
5. After Quotation: A Deviation Table to Calibrate the Basis
Allocation amounts are estimates and must be recalibrated with actual data. Create a monthly deviation table for each customer with only five columns: customer, allocation amount, actual amount, deviation rate, and main deviation items.
The rules are simple: if the deviation rate exceeds 20% for two consecutive months, a quotation review is triggered; if the deviation is concentrated in external failure, prioritize changing the terms (sharing screening costs, penalty caps, inspection methods); if the deviation is concentrated in internal failure, prioritize improving the process (poka-yoke, process parameters, incoming inspection requirements). After one year, the allocation basis will be updated from industry empirical data to your own data, significantly improving the accuracy of the quotation.
6. Four Common Misunderstandings
① Using the plant-wide average nonconforming rate for allocation. The average nonconforming rate masks the differences between customers, effectively turning the new basis into the old one.
② Allocating one-time costs in the first year. The investment in PPAP, DV/PV, and dedicated inspection tools should be spread over the lifecycle supply volume. Allocating them in the first year makes the first order appear unprofitable, leading sales to delete them directly.
③ Allocating but not including in the quotation sheet. If the allocation amount remains in the cost sheet and the quotation sheet still shows a whole number, sales will still negotiate based on the whole number. The allocation must be noted in the quotation line, specifying the corresponding quality conditions.
④ Treating penalties as rare events. Penalties are not "just in case," but probabilities. Multiply the historical trigger frequency by the amount, which is more reliable than "hoping it won't happen."
If quality costs are not included in the quotation, they will only be absorbed into the gross profit; each line on the quotation sheet is an opportunity to clarify the quality conditions.
Knowledge code: 4.3.1
Version: v20261023
Author: QTank QTank is dedicated to providing systematic professional knowledge, methodologies, and practical tools for quality management practitioners, helping companies continuously improve their quality capabilities.