Check me if I'm wrong here but... does it matter? Since you don't generally take AoO on YOUR turn, but rather during OTHER characters turns it shouldn't be relevent. Since you're not going to be taking an AoO until AFTER your turn is over it doesn't matter if your AoO is refreshed at the start of your turn or at the end. Again, check me if I'm wrong, but your own actions on your turn can't FORCE an AoO for you against someone else - only the actions of others allows you to take an AoO, meaning again that it doesn't matter when your AoO is "refreshed".
There may be some odd, tortured situation that I'm not thinking of that makes it possible for you to start using AoO's on your own turn but...