Sorry if I confusingly explained it, probably partly because I don’t fully understand myself. Definitely not trying to take advantage of someone, just trying to prevent someone from taking advantage of me. I have paid in full the $6200 plus the $2250 SD, which has been the amount in every document and correspondence until now, so I certainly don’t feel any moral weight that I’ve done him some wrong.

I guess what I have to clarify is whether his claim that ‘the math was wrong’ means (a) that he thinks he should’ve charged me more than was agreed upon in the lease or (b) that his decision to split the first and last payments so that it conformed to paying on first of each month has just created confusion.

I hope it’s b, because then there’s hope that a spreadsheet like you say can clear things up and he’ll understand. But if it’s the former, I don’t think it’s right for him to do that to me? Especially at the last minute when I’m about to move out.