Lower Jaw Advancement Surgery. What is Normal Hospital Stay? Is 7mm Advancement Enough? (photo)

hi am 22, am getting a lower jaw advan of 7m.m in length and my surgery is about 4hrs. so how long do i have to stay in hospital for.like 1day.?? 2day 6hrs?? and also how much is the maximum advancent possible..?? because 7 m.m is nothing!..am paying heaps and i thing 7m.m seems less than what i should get. and my orthodontist is making excuses.. please tell me if i need to change my dentist or what.