This may be a bug, but I noticed my ontime is down from 37-42 days (Don't know the exact one) down to 19-24 hrs. I don't know if this is a bug, or if it's due to my being off for so long, or if it happened server wide (Probably not) It's not super important, I just like big numbers
When you change your name, the plugins all register you as a new player. This is why the admins have to move all your information to your new name manually (see ^newname). However, your total ontime does not come with that movement of information, so, yes, it is because you changed your name.