Silent Commission Errors: The Ones Nobody Spots Are the Ones That Hurt Most

AlphaTradeZone via Pexels

Every RevOps and finance lead knows about the loud commission errors — the rep who spots a missing deal 20 minutes after payroll runs and won't stop emailing until it's fixed. Those get resolved. What quietly ruins commission programmes is the other category: the errors nobody spots at all. The £3,200 that should have been £320. The tiered accelerator that never triggered. The clawback that was applied twice. Nobody complains, so nothing gets fixed, and the numbers get worse every quarter.

TL;DR: Silent commission errors are miscalculations neither the rep nor finance notices — usually overpayments where reps don't want to check, or underpayments too small to argue about individually. In our experience they cost more than the loud ones because they compound over months, they undermine trust the moment they're eventually discovered, and reclaiming an overpayment from a rep is legally awkward under the Employment Rights Act 1996. The fix is not a cleverer plan — it's real-time visibility, a proper audit trail, and a manager-owned pre-payroll sanity check. This article walks through where silent commission errors come from, what the law actually says about reclaiming them, and a concrete framework to catch them before payroll runs.

Reps don't lose faith when a number is occasionally wrong. They lose it when they can't see how it was built — and a correction lands with no warning.

What is a silent commission error?

A silent commission error is any miscalculated payout that goes unchallenged. It doesn't generate a Slack message, a ticket, or a spreadsheet flame war. Sometimes that's because the rep hasn't noticed — commission statements are dense, and if the total "looks about right", human beings stop reading. Sometimes it's because the rep has noticed, but the error is in their favour and speaking up feels like volunteering to be poorer. Either way, the calculation is wrong and stays wrong.

We've lived this one first-hand. On a single deal, one of us was once paid £16,000 in commission instead of £1,600 — a decimal-place error in the payout logic. Neither the rep nor the company spotted it for roughly two weeks. When it finally surfaced, the immediate reaction wasn't "phew, caught it" — it was, "how many smaller errors of this exact shape are we not catching, across every rep, every month, forever?" That question is what this article is really about.

Why do silent commission errors matter more than loud ones?

A loud commission error is self-correcting: the rep raises it, finance investigates, the number gets fixed, and everyone moves on. The cost is a few hours of RevOps time. A silent commission error has three costs that stack on top of each other:

1. The direct cash cost. An overpaid £1,000 is £1,000 of gross margin gone. Multiply by a 20-rep team and a few months of drift, and the number stops being trivial.
2. Employer NIC and pension leakage. Commission is chargeable to tax as employment income (see HMRC's Employment Income Manual EIM64615), which means an overpayment also carries Class 1 employer NIC and — if the rep is enrolled — employer pension contribution on top. You are overpaying the wrapper as well as the payment.
3. The trust cost when it's eventually discovered. This is the biggest one. A quiet correction to a rep's expected earnings, with no clear audit trail, breaks the plan psychologically. Reps stop believing their statements. Some start shadow accounting in their own spreadsheets, which then becomes the source of truth in every dispute.

Where do silent commission errors actually come from?

Most silent commission errors are not exotic. They cluster in a small number of predictable places:

The common thread: they are all small enough per line that no single one triggers a challenge, and they all live in the seams between systems (CRM, spreadsheet, payroll, Xero). Our own take, from watching this happen across finance teams: contract complexity spikes past around £100k. Comp logic that works fine on a £10k 14-day SMB deal quietly breaks the moment opt-outs, ramps, custom start dates and security-review delays enter the picture.

A worked example: how a £14,400 silent error hides

Take a 20-rep team, mixed 70/30 base-to-variable, average commission earnings of £2,500 a month. Suppose the CRM-to-spreadsheet handoff rounds each deal's ACV up to the nearest thousand before commission is calculated — a small "convenience" that nobody flagged when the sheet was built.

Across 20 reps closing an average of three deals a month, that rounding averages roughly £60 of over-commission per rep per month. £60 × 20 reps × 12 months = £14,400 a year in overpayment. Add employer NIC (at the rate applicable from April 2026 — see our note on employer NIC on commission) and employer pension on top and the true P&L hit is meaningfully higher.

No individual rep will ever complain about £60. No individual line looks wrong. Finance close the books each month cleanly. And the error compounds silently until someone runs the reconciliation from first principles — which almost nobody does.

What does the law say about reclaiming an overpayment?

This is the part that turns a silent commission error into a live employee-relations problem the moment it's discovered. Under section 14 of the Employment Rights Act 1996, the general prohibition on unauthorised deductions from wages (in section 13) does not apply where the deduction reimburses the employer for "an overpayment of wages". In other words: yes, employers can generally recover overpaid commission by future deduction, without needing separate written consent.

But "can" is not "should". Acas guidance is explicit that employers handling overpayments should notify the worker first, agree how the money will be repaid, and — for larger or older overpayments — allow a repayment plan. Simply clawing £16,000 back from next month's pay is legally defensible but culturally catastrophic. There is also a common-law "estoppel" argument reps can sometimes deploy: if they queried a payment, were reassured it was correct, and spent the money in reliance on that, recovery can be contested.

How do you catch silent commission errors before they compound?

There is no elegant answer here — the only thing that works is systematic pre-payroll review, plus visibility for the rep. A workable framework has three layers:

The underlying point: disputes and errors are a visibility problem, not a maths problem. A cleverer plan does not fix silent errors. Real-time transparency and a proper audit trail do.

Where spreadsheets fail specifically

Spreadsheets are the single largest source of silent commission errors in UK sales teams below ~200 reps. Not because Excel is bad, but because the failure modes are invisible: a formula referring to $B$14 after row 14 was deleted, a VLOOKUP against a stale rate card, a manual override applied for one edge case and never removed. There is no audit log; nobody knows what changed between last month's file and this month's. When we compare the true cost of spreadsheets vs commission software, silent errors are usually the biggest single line item — and the one nobody had modelled.

The cheapest commission error is the one caught before payroll runs. The most expensive is the one you find eighteen months later in an audit.

Frequently Asked Questions

Can we legally reclaim an overpayment of commission from a rep?

Generally yes. Section 14 of the Employment Rights Act 1996 exempts overpayments of wages from the unauthorised-deduction rules in section 13, so employers can normally recover an overpaid commission through future deductions. But Acas guidance recommends notifying the employee first and — especially for large amounts — agreeing a repayment plan rather than deducting the full sum in one go.

Is commission always taxable as employment income?

Yes. HMRC's Employment Income Manual (EIM64615) is clear that commission which counts as earnings from an employment is chargeable to tax as employment income and must go through PAYE. That means overpaid commission also carried PAYE, employee NIC and employer NIC — recovery mechanics need to unwind all of that, not just the gross figure.

How long can a rep claim for an underpayment of commission?

Unpaid or under-paid commission is treated as an unauthorised deduction from wages. Under Acas guidance, workers have three months minus one day from the date of the deduction (or the most recent in a series) to bring an employment tribunal claim, and can typically claim up to two years of back-pay where deductions are linked. That's why underpayments are dangerous even when they look small: they aggregate legally as well as commercially.

What's the single best control against silent commission errors?

A manager-owned pre-payroll review, tied to the real contract terms rather than the summary spreadsheet. In our experience the most costly silent errors happen because finance pays on the signing-day gross value before opt-out or ramp clauses resolve. Making a specific human — usually the sales manager — sign off on each payout against the actual contract catches the majority of them.

How do silent commission errors erode trust even when reps benefit?

Because the correction always lands eventually, and it lands as a surprise deduction with no clear explanation. Reps who were quietly overpaid for six months experience the reclaim as an arbitrary pay cut, regardless of the underlying maths. That's why real-time visibility matters more than plan cleverness — it prevents the class of error where a rep is asked to trust a statement they never had the tools to verify.