You can correct me if I'm wrong, but I'm pretty sure Lefort I is just maxillary movement and is rather common for fixing occlusions....
I think lf3 is the one (typically) reserved for true deformity or trauma.
I've been trying to find good papers that show the long term success and % of relapse but I haven't searched around enough, and wouldn't your surgeon be able to provide some ballpark estimate as to the number of people he/she has worked on and seen relapse? Or would it not be reliable?