TriCare for Life

I'm on Medicare and TriCare for Life supplemental. I'm trying to find out from Tri Care for Life if Lap Band is covered - surgeon's office person says she's not sure. Does anyone know about this? My surgeon's office says Medicare covers lap band and other type of bariatric surgery. Medicare does not send out approval letters according to the office person. Sooo have any of you had experience with Medicare coverage denial? (I am almost 40 bmi with co-morbidities.) The insurance person at the surgeon's office says there have been no problems with Medicare paying. Talk about stress as you all know all too well.