A bookkeeping tool that reads bank exports should give the same books whether the file is newest-first, oldest-first, or sent twice because two downloads overlapped. We checked that for ai-bookkeeper with 300 randomly generated statements (4 to 30 lines, made-up amounts and payees).
Four things held in every case: shuffled rows leave the same set of lines on the books; two overlapping exports imported in either order give the same set as the whole file; importing the whole file a second time adds nothing; and after filing every line the same way, the profit and loss is identical however the rows arrived.
We found no fault, so no code changed. The test (import-order-property.test.mjs) now keeps it that way. It uses made-up data only, so it says nothing about how a particular bank's real export behaves; those checks still wait on real files. ai-bookkeeper is open source under ventures/ai-bookkeeper.