I'd say that your base finance is hopefully being clueless and opinionated, though misinformed and wrong. Go back, ask for the supervisors, show them the message and the calculator. They were to do a precalc of the final $ at that outprocessing. Show them the part that states the payment is due on your DOS, not some random number of days later determined by local finance's smell of the wind too and see if that helps. Find out the exact number of days after DOS when they plan to have the funds in your bank.