Can a working capital dispute come down to which accounting standard the seller used?

Yes, and this is one of the more common sources of working capital disputes in practice. If the purchase agreement does not clearly pin down a single, consistent accounting policy and methodology, requiring the closing statement to be prepared using the same treatment, consistently applied, as the seller's own historical financial statements, a seller and buyer can end up genuinely disagreeing about figures that are each technically defensible under a different, otherwise acceptable accounting treatment.

This kind of dispute is not usually about someone acting improperly; it more often reflects that generally accepted accounting practice can permit more than one reasonable way to treat certain items, and without an agreed, specific methodology locked in ahead of time, both sides can arrive at very different final numbers while each believing their own approach is correct. A well-drafted working capital adjustment mechanism addresses this directly by specifying the exact accounting policies, and often the specific line items and estimation methods, to be used for the closing statement well in advance, precisely to prevent this kind of disagreement from arising after closing when positions have already hardened.