A friend of a friend who works for Intuit told me they intentionally make it difficult to make PPR payments because Intuit has to a pay a fee to the bank for each individual transaction, so they want to encourage preparers to make one large deposit and work off that.

I did that a few years ago and Intuit refused to refund the balance after tax season, so now I just do as many small transactions as it takes, and I take comfort in the fact that Intuit has to pay higher fees for making this process as inconvenient as possible.