Insurance Issue--Medicare/Tenet 65/UHC Indemnity

I will have my initial consultation appointment for WLS on Wed. My insurance is Medicare (primary) and United Healthcare Indemnity (as secondary). I am most interested in BPD-DS for myself. Has anyone been "switched" and covered by Medicare? I spoke with Dr. Warden's patient advocate today but there is some concern and confusion as to whether Medicare will cover the BPD-DS. Additionally, I may be signing up with Tenet 65 as my "supplement" to Medicare. Anyone have any experience with any of these insurance issues and whatever "out-of-pocket" charges, what the R&C charges that may be approved by Medicare and/or UHC? Any info on this would be of great help!