In the IRS we trust

So I did my taxes this year and I owed. Poopy. I filed a form requesting and installation plan. After two weeks I called to get the status because I hadn't heard anything via mail or phone, (very grown-up) and I was told that my request had been approved, my payments would be $25/mo, first payment due July 25th, but that my first payment needed to be for $43 as a set up fee. I sent my first payment in but forgot it had to be for $43 and sent $25. A week later I sent in a check for $18, cool, I'm caught up. I got a reminder letter today for my July 25th payment. I called and found out that because I sent in the first check so soon, it wasn't applied to my installment plan, but the balance itself. So the system hasn't seen a payment for $25, only $18, and it doesn't recognize partial payments. The woman told me that the computer system is REALLY old, and there is basically no human verification or review of the records. So I have to make a payment of $7 by the 25th to keep my account current, (and that has to be made at an IRS office because the IRS rep said if I mailed a check now it would never post to the account in the next two weeks) and then the $43 payment in August. Oh so efficient, I love it.