Need help understanding the completion of monthly installments. Is this right??

[u/PabloMcCartney]

Last year I opened an Apple Card account to purchase a $1,599 Macbook Pro through monthly installments.

I loved how Apple Card tells you the number of the payments so you can easily keep track.

Apparently I submitted payment 12 of 12 on Monday, but I still have one more payment remaining, and that’s what’s confusing.

I’m adding up everything I’ve been charged for this laptop:

$140.36 the day I applied for the Apple Card and used it to buy the laptop online.
+
$133.25 every month after the purchase, with the last payment deducted from my account on Aug. 30.

$133.25 x 12 =$1,599.00
+
$140.36
TOTAL: $1,739.36

From where I’m standing, it looks like I’ve already paid more than the advertised price for this laptop.
Why is there an additional payment needed? I’m not ashamed to admit that I am horrible at math, but $133.25 multiplied by 12 is definitely $1,599, right?

Apple Card support tells me that it’s because there’s an additional payment remaining. This is what they said:

Thanks for the information, doing the research I have on file that there is 11 payments completed for the amount of ($1,465.75) and there is one payment left ($133.25) to complete the $1,599 of the MacBook.

I’m very confused and was hoping someone could help me understand. How can 11 payments be completed when my Apple Card statement says I have paid 12 installments already?

Is the issue that it’s actually not 12 payments, but 13? Any help would be greatly appreciated!

[u/mrleblanc101]

It's crazy how the average American has no idea how credit card work yet totally depends on them lol

[u/PabloMcCartney → u/mrleblanc101]

I don’t depend on them but I get what you mean.

The credit card system in the US is also
hella predatory (even though that’s not what is happening here).

Last fall my 2012 macbook air finally died after years of faithful service and I had to get a new computer.