All I have been saying is that no USA bank will stop anyone from paying off a zero percent consumer loan at whatever rate they wish to pay it off. You can pay the thing off over the full term, a shorter term by higher payments, or all at once, at any time within the term limits. No bank will stop you from doing that - so there is always a way to do it, via a web account with the Bank, a phone call, a walk-in appointment, whatever. It’s actually in their interest to get their money back sooner than later since the default debit payment schedule already ensures payment within the zero percent terms, so they are not making money on most of these loans in the first place.
So when people post here asking can they pay their Apple upgrade program loan or their Apple finance loan off early, I always tell them yes, because there is always a way to do it. And the terms of your loan should include how to do it, although no one seems to read or even keep those terms documents you receive when you finance.
For interest bearing loans, a Bank can impose early pay-off fees to offset the lost interest revenue, although again, they rarely would stop you or refuse your early payment or pay off as that is why they built in the prepayment fee in the loan terms (so they still come out ahead).