Nope, you're good. I can't remember, off the top of my head, whether you actually get paid for the 14th when you're on AT, but I don't think you do. If you were on ADT, you would not, though. I'm pretty sure AT works the same as ADT, which allows you one paid travel day and then pays for the ticket on the second travel day but doesn't pay you per diem. It's confusing, but it works out in the end.
I would just double check w/ your NOSC/Command, though, and make sure neither you nor they are expecting to pay you for an extra day of AT. Not a huge deal if you did, since everyone gets 29 days right now, but probably something to double-check with them about.