A small difference on every other job
The accounts person is keying a dealer's parts invoice. The rear bumper on the invoice costs a little more than on the estimate. So does the tail lamp on another job. A bracket that was superseded has a new part number and a new price. None of it is large, and nobody has time to chase it, so the invoice is paid as it is.
Across a year of repairs, those small differences add up. Some should have been raised with the supplier, some with the work provider, and some should have prompted a change to which supplier you use.
Estimate prices and invoice prices are never lined up
The estimate is built in your estimating system with the parts prices it holds. The supplier invoices from its own system, with its own prices, discounts and surcharges. The two are compared only if someone does it by hand, and when invoices cover several jobs, that is slow work.
- Supplier prices change between the estimate date and the order date.
- Discount levels agreed with a dealer are not always applied on the invoice.
- Superseded part numbers break simple matching.
- Delivery charges and surcharges appear on invoices without warning.
A worked example: an estimate lists a headlamp at the price in the estimating data. By the time the car is authorised and the part ordered, the dealer's price has gone up, and your agreed discount was not applied because the order went through a different branch. Two separate reasons for one difference, and without a comparison neither is seen.
Where the margin goes
Parts margin is a meaningful part of the income on many repairs. Differences that are not caught reduce it on every job. Where your agreement with a work provider allows a price change to be raised, you cannot raise it without knowing about it. Where the supplier is at fault, the credit is never requested.
There is also the time spent checking by hand, which usually means checking a few invoices carefully and the rest not at all.
How we build a parts invoice check
- Supplier invoices are read as they arrive, by email or from supplier portals, using document extraction for PDFs where needed.
- Each line is matched to the job, by the order reference or registration, and to the estimate line for the same part, allowing for superseded numbers.
- Differences in price, quantity or discount are listed per invoice, with the estimate price alongside.
- Surcharges and delivery charges are shown separately so they can be checked against your supplier terms.
- A person decides for each difference: accept, query the supplier, or raise with the work provider through your usual route.
- Accepted invoices are passed to your accounting system, such as Xero or Sage, where it allows, with the difference recorded.
| Difference | Likely cause | Usual next step |
|---|---|---|
| Price above estimate | Supplier price change | Accept or raise with provider |
| Discount missing | Wrong account or branch | Query supplier |
| Different part number | Supersession | Confirm and accept |
| Unexpected surcharge | Supplier terms | Check terms, query |
What you can recover from a work provider or supplier depends on your agreements with them. The check shows the differences; the decisions stay with you.
What the accounts desk sees each week
Invoices with no differences go through with a glance. The few with differences are listed with the reason and the amount. Supplier queries are raised while the invoice is fresh. Over time, the pattern shows which suppliers apply your terms correctly and which do not.
You also get a clear view of how much parts price movement is affecting your repairs, which is useful context at any work provider review.
Signs you are paying more than you think
- Parts invoices are paid without comparing them to estimates.
- Supplier discounts are not checked on each invoice.
- Surcharges appear and are simply paid.
- Price changes between estimate and order are never raised.
- Nobody knows the total of these differences over a year.