Anybody pay the difference b/w the surgery they want & the one the ins co would pay for?

I'm seeing my surgeon for the first time this Friday & have already done the nutrition classes & psych eval.  I'm almost positive my insurance will cover a bariatric surgery for me b/c I meet their criteria & they're known for quick approvals in that case.  The problem is I really think I would prefer a DS over an RNY.  I've done  A LOT of digging into this & have finally fount out that my insurance company will cover DS only if an RNY is deemed too hazardous by the facility/hospital.  The dr at the informational session said that they mostly do lap bands & rny's and will only do DS's in exceptional cir****tances, but didn't elaborate.

I can't find any research under what conditions an RNY is deemed to dangerous where a DS would be more appropriate.  My insurance company is doing a "pilot study" in which they're temporarily covering DS's if RNY is too hazardous.  Has anybody else been able to pay the differece b/w what the insurance company will cover & the surgery you actually want, even if they were different surgeries than the DS and RNY?

I know the surgeon has experience with DS's and RNY's, but I'm guessing will try to talk me out of it based on the informational meeting.  This is also distressing to me b/c challenging the insurance company must entail the support of your doctor.  That's just my assumption, but it seems pretty basic given.