The account has been open so long the people have left
Nobody still here knows what was agreed, and the file is all that's left of it.
What's happening?
The job finished years ago and the account never did. The surveyor who ran it has gone, the project manager has gone, the other side's people have rotated too, and the deals that were done, in site huts, on calls, in heads, went with them. What is left is a file, and new people on both sides inheriting positions nobody can explain.
An account can only close on what can be shown, and institutional memory was never evidence anyway. Read cold, the file usually says more than anyone expects: agreements half-recorded in minutes, sums certified and then quietly reversed, items both sides stopped arguing without ever resolving, credits nobody claimed.
The reconciliation, what was certified, what was paid, what was agreed, what is genuinely still open, is buildable from paper alone, and it is the only version of the account that does not depend on who is still in the building. The one clock that matters is legal: the longer an account sits, the closer the time limits for enforcing anything creep, and where that might be near, the date is worth confirming with a solicitor early.
Restated that way, the account stops being a haunted house and becomes a decision: what it is worth, what it would cost to fight, and what number closes it.
The solution
The file made to say what the people no longer can.