Well, NMAC's new site is just neat-o.
I didn't sign up for the "new" account soon enough so they didn't make my payment yet (have to agree to new terms). So now my payment is "past due" by 2 days.
Now we get to the really dumb part... The "Amount due" also includes next month's payment. So the "total amount due" is actually TWO PAYMENTS.
So it shows:
Due 10/18: <payment amount>
Past due: <payment amount>
Total amount due <2 payment amounts>
And even even you try to "make a payment online" it tries to get you to pay both payments.