You would assume so, but the whole problem was that the Horizon computer system would lose transactions. It might lose the transaction where the customer paid by credit/debit, and the post office received the money directly. Or it might lose the transaction that recorded the check the postmaster sent to the post office to reconcile accounts. Again, the Horizon system never had a reliable record of what transactions had actually happened. Once there were discrepancies, it was always easy for it to look like the postmaster had made a mistake or committed theft.