I experienced the same frustration. I finally decided to hit the "Mark as Paid" button next to the schedule payment online button and it takes you to the screen you are used to seeing with the old "Make Payment" button. You can select the account you want to pay from.

They rob you when you let them process payments, they rob you with subscription based software, now they want more money to schedule a payment in their program. It's getting pretty ridiculous. How bout with our subscription all the stuff the software is supposed to do is included. How about that?