Revision - insurance if you haven't regained back to BMI

Hi all,

Looking for some good ideas. I had a lap band in 2006 ad have a slip. It needs to either be replaced or converted to a sleeve (the surgeon's recommendation). My original surgery was covered by insurance and the qualifications for my old insurance company and my new one are the same. I had a 38 BMI and co-morbidities. I lost 75 pounds but am now back up 25. BCBS Federal says they cover all the relevant procedure codes including revision, replacement and sleeve gastrectomy. But since I'm no longer morbidly obese they won't approve the surgery even though it's now deemed medically necessary. This is insane! 

Anyone get approved for a revision after losing weight and have tips?

Thanks,
Britt