Billing reconciliation: catching scope creep before you write it off
A matter was scoped as a fixed fee. Three months in, the client has called nine times with questions that were not in the engagement, sent two documents that needed reviewing, and asked for a summary for their board. Someone helpful did all of it.
None of it was billed. It was not a decision. Nobody ever sat down and decided to work for free. It arrived one favour at a time, and it turns up at year end as a write-down, next to a realization figure that a partner will describe as disappointing.
What billing reconciliation is
Reconciliation is a check that runs on every invoice, and on the time behind it, before it leaves the firm. It compares what is being billed against two documents the firm already has: the engagement letter and the rate card.
It has two halves that behave very differently, and the difference matters.
The first half is arithmetic and rules, and it is exact. Hours multiplied by the rate for that person’s role. Line totals against the printed subtotal. The total against the subtotal less the retainer. The amount in words against the amount in figures. Dates inside the billing period. The engagement start date. Time recorded in the increments the letter specifies. Third-party costs above the threshold the letter set. People billing who are not timekeepers. Payment terms that do not match the letter. None of that requires judgment. Every one of those has been an invoice that went out wrong at some firm.
The second half is judgment: is this line inside the scope the engagement letter describes? That question cannot be answered by arithmetic, and it is the one that costs the most money.
Here the design matters more than the accuracy. When the system says a line looks out of scope, it must quote the sentence in the engagement letter it relied on. The firm’s own copy of the letter is then checked for that sentence. If the sentence is not there word for word, the finding is downgraded to something a person should look at, rather than presented as a conclusion. A billing dispute built on a misquoted engagement letter is worse than no check at all.
What comes out is a list, not a gate. Each item names the line, the rule or the clause behind it, and the amount at stake. A person decides. The invoice is not held, the partner review is just shorter and better aimed.
Nothing is changed in the accounting or practice management system without someone approving it.
Does a firm your size need it
Start with one number: what did the firm write off last year, and can anyone say why?
Most firms have the first number and not the second. Write-downs are recorded as a single figure per matter, decided at the end, with the reasons living in the memory of whoever made the call. A firm in that position cannot tell scope creep from bad estimating from a client who was always going to be difficult, so it cannot fix any of them.
The strongest signal is fixed-fee and capped work. Hourly billing at least records the extra time even when it is later discounted. Fixed fees absorb it silently, and the firm finds out at the end.
The second signal is disputes that arrive after the invoice rather than before. A dispute is a check the client ran that the firm did not.
The third is realization that varies by partner rather than by matter type. That means the discipline lives in individuals, which means it leaves when they do.
Across the systems we run for firms and service businesses, this check runs at volume: 27,167 service requests taken and 20,871 matched to a provider, with every job’s charge checked against its approved scope before the invoice and before the contractor was paid. The check runs in the seconds before money moves, which is the only moment it is cheap.
What it costs
Reconciliation is built as a fixed-price phase inside a plan. The price depends on how many fee arrangements the firm uses, which systems hold the time and the invoices, and how consistent the engagement letters are. A firm billing hourly against one letter template is a smaller build than one running fixed fees, retainers, contingency and recurring work side by side.
The audit prices it as a phase before anything is built, and credits its own fee against that phase if the firm goes ahead.
Running costs are low. Most of the rules are arithmetic against the firm’s own data, and only the scope judgment needs a model at all.
The cost that is easy to miss is the state of the time entries. A check can only be as good as what it reads, and “attended to matter” tells it nothing. Most firms find that entry quality improves during the first phase without anyone being lectured about it, because people see their own gaps in the same week they made them rather than at the end of the quarter.
What the first week looks like
The first week is spent on invoices that already went out.
We take a quarter of them, with a bias toward the ones that were disputed, discounted or written down, and reconstruct what happened. What was billed, what the letter said, where the two parted company. That exercise usually produces the first real finding of the engagement, which is that the same two or three things go wrong repeatedly.
The rules are written from the firm’s own engagement letters and rate card, not from a generic template. A rule that does not trace back to something the firm wrote down does not go in.
Then the rules run against invoices the firm has already sent, where the outcome is known. Every finding is checked: was this a real leak, or noise? Noise gets tuned out before anyone sees the system in a live billing run. A reconciliation tool that cries wolf in its first month is ignored by its third.
By the end, the check is running ahead of partner review, and the people who prepare invoices have agreed the findings are worth reading. That is the condition for go-live, in this build and every other one.
The full scope is on the service page: /services/billing-pipeline-capacity. To read a fictional firm’s invoice review, then change a rate or a date and watch findings appear and disappear, the demo is here: /demos/scope-check.