I'm not familiar with how it works as I am retired. I do have a friend though who did indoc at a major and then deployed. Hasn't been to training yet. Probably different as this guy is a Guardsman, not active duty.

The bottom line is that I don't think your future employer cares much if your availability changes by a few weeks or months. They understand. I'm sure they have plenty willing to move up a class date. That said, get your number as soon as humanly possible.