These are not signs of dishonesty. They are the line items that default settings and busy back offices produce, and they survive precisely because they look unremarkable.
Updated 2026-09-03 · 5 min read
Billing systems have defaults. A job type gets created once, with a set of standard charges attached, and every subsequent job of that type inherits them — whether or not a service contract makes them chargeable. The result is a small number of line items that recur across invoices and rarely get questioned.
1. Emergency or after-hours callout fees
A contract will often promise a response time — four hours, next business day — without anywhere authorising a fee for meeting it. The promise is an obligation on the vendor, not a permission to charge. If a callout fee appears, look for a clause that specifically allows it, and check whether the contract rate schedule already includes an after-hours labour rate that covers the same thing.
2. Shop supplies and miscellaneous materials
Usually a percentage of the labour total, often three to five percent, described vaguely. Under a parts-and-labour plan the materials used in a covered repair are typically already covered. A percentage-based supplies charge on top is worth asking about, particularly when the parts themselves were supplied at no cost under the contract.
3. Rate drift
The quietest one. The contract fixes labour at a rate; the invoice bills slightly above it. Twenty dollars an hour across four hours is eighty dollars on a single invoice, which nobody escalates — and the same eighty dollars every time, for the life of the contract. Check the rate against the schedule on every invoice, not just the ones that look unusual.
Contracts frequently set different rates for standard hours, evenings, weekends and holidays. A rate that looks wrong may be the correct after-hours rate, so check the service time before raising it.
4. Travel or mileage billed twice
Where a technician attends more than once for the same fault, travel is sometimes billed on each visit even though the contract allows it once per incident, or includes it entirely. Return visits for the same underlying failure are worth grouping and checking as one job rather than as separate invoices.
5. Parts billed under a plan that supplies them
The most valuable single line to catch. A covered component billed at full price because the job was raised as time-and-materials rather than against the contract. This is usually a data entry error rather than anything deliberate, and it is normally corrected without argument once the covered schedule is pointed at.
6. Diagnostic time on a covered failure
Where a plan covers parts and labour for a failure, the time spent diagnosing that failure is usually part of the covered labour. Billing diagnosis separately, then billing the repair as covered, charges you for half of a job the contract already pays for.
How to check these without reading forty pages
Every one of these comes down to the same question — is there a clause that authorises this specific charge for this specific unit on this specific date. That is a mechanical check, which is exactly why it can be automated, and exactly why it so rarely gets done by hand at four in the afternoon.