Thank you both for the responses.
Randy, what I meant by the original determination being updated is simply that the map and date are updated, but the determination keeps the same number. We don't order or go pull a new one.
David, I remember reading abou that requirement, but hadn't considered it until now. I will reach out to the vendor and find out. Part of me is skeptical that they would guarantee the accuracy of both without charging again, but that price may be built into the service; that relatioship pre dates mine at the bank.