Hi Cricketcree,
I have GEHA, I don't know if it is connected with United Healthcare. GEHA for me only required that I have a BMI of 40 or above or if my BMI is below 40 that I have a comorbidity, have documented 6 months of attempted dieting (the months leading up to surgery count towards that) and that I use a surgeon or practice listed with the "centers for excellence". My DR/practice had just lost their accreditation, but after I appealed and received my approval I was told that the "centers for excellence" only means they've done more than a certain amount of surgeries a year (I think the number is 285?). My appeal only took a week to sort out.
Be sure to check and see if your GEHA plan has a yearly limit on the amount out of pocket you pay for medical. I spent $500 prior to my surgery and my GEHA's policy is that after I reach $7000.00 (yearly) I can't be charged any more out of pocket for medical, so my remaining amount was only $6500.00 (altogether w/out insurance would have been aprox. $45,000).