Which vendors got coded two different ways

Drop a coded transaction export. This groups every vendor by the accounts their transactions were posted to, and puts the odd one out first — because a vendor coded the same way forty times and differently once is almost never a deliberate choice.

Two different findings, and only one of them is a problem

A vendor appearing under several accounts is not automatically wrong. A hardware store legitimately sells you shop supplies one week and a tool the next. So the results are split in two, and the order matters more than the count:

• An outlier. One account holds the clear majority of a vendor's transactions and another holds one or two. That shape is a slip — a rushed month-end, a new bookkeeper, an autofill that guessed. These come first, with the odd rows' line numbers so you can go straight to them.
• A genuine split. The vendor's transactions are spread across accounts in comparable numbers. That usually reflects how you actually buy from them, and it is shown separately so it does not drown the list.

The threshold is deliberately blunt: an account holding at most a quarter of a vendor's rows, where some other account holds most of them, is the odd one out. Anything less clear-cut is called a split rather than guessed at.

Why it also totals the money

Each account line carries its share of the vendor's spend, because the count and the amount tell different stories. One miscoded transaction out of forty barely matters if it is $18 and matters a great deal if it is $18,000 — and the count alone cannot tell you which you are looking at.

What it does not do

It reads and reports; nothing is written. It cannot know which account is the correct one — only that the same vendor was treated two ways. Account names are compared as written, so 6120 and 6120 Office Supplies count as two different accounts, which is itself worth seeing if your chart is entered inconsistently.