The Math Checks Out. I, However, Do Not

I am an MNUFC season-ticket holder, and despite not being able to go to even one home Match for the 2020 season, I still am an STH.  Thankfully the organization decided not to be greedy dicks and carried over my balance to pay for my season tickets for next year -- that is, if we're allowed into Allianz Field next year.  Who knows?

There were no refunds, however, so it was just a matter of figuring out how much I have already paid before the team froze monthly installments (for which I am charged on my credit card) for four months, then spreading that remainder over another 12 Months for what is now my 2021 ticket.  I reached out to a season ticket representative (serendipitously, I saw on Twitter that the person who was once my rep, with whom I was not following on Twitter, quit; thankfully I do follow MNUFC's Twitter, and I believe that account re-tweeted her farewell to the team) who told me all this and, consequently, my new monthly installment would be almost twelve bucks.

Imagine my surprise, then, when I looked through my credit card statement and saw that I was charged more than $35 in August, and then less than $10 in September.  It seemed obvious they were trying to make up for the incorrect charge.  But I thought that this new monthly charge of ten bucks per month was too high considering I was charged so much from my remaining balance (about $140).

I had to reach back out to the rep I reached out to before and asked what the heck was going on.  Turns out that SeatGeek did not apply the new monthly installment of twelve bucks because there was a screw-up and someone somewhere did not apply all the money I had already paid for my season ticket; that $35 was the amount of my old installment.  And instead of redoing the installment, SeatGeek and MNUFC apparently just went with it.  And so, with my new new remaining balance, spread out over 11 Months instead of 12, the rep said I will be paying about ten bucks through, uh, August.  And I just did the math and, yep, he's right.

All well and good.  My problem is with myself.  How in the hell did I screw up the math and believe I was being overcharged?  I did the difference thing -- $35 was $24 higher than what should have been my installment, but this new installment was only $2 below that old installment, and that means it would take more than 12 Months before I finally got even with the amount gouged out of me in August, and that didn't seem right ... but the math checks out, and I was wrong.  I swear if I were younger -- or if I actually thought it through -- I wouldn't've screwed up the math.  Dammit, there's something wrong with me.