The builder's final bill doesn't make sense
The build is nearly over, but the last bill contains changes, allowances and quantities you cannot reconcile.
What's happening?
A final bill gathers up decisions made across the whole build. It can include agreed changes, provisional sums, measured work and credits for work that was not completed. By the end, those items are often spread across emails, drawings, invoices and conversations, so the total is hard to check from the bill alone.
Start by putting the records beside the bill and tracing each line back to what was agreed or built. Keep unfinished and defective work visible too. That creates a working account: a record of what each item is, what supports it and what still needs an answer before you decide how to respond.
The solution
Put the account and the remaining work into one clear record before making decisions about the close-out.
If you would rather it were done for you, Final Account & Close-out is the service that does it.