Help!! Medcost question. . .

Hello everyone.  I have Medcost Preferred and when I contacted my carrier to ask about WLS, I was told that the only requirement was a BMI over 40 and that it be medically necessary.  I looked up my policy on line and all it said was that Gastric Bypass is covered as a regular benefit.  I also called the customer service number on my insurance card and the lady in the benefits department there told me the same thing.  That's all the info I could find regarding my policy. I have talked to a couple of people who have had the RNY who had Medcost and both of them said that they had to have a 6 month documented diet record (ex: Weigh****chers, Jenny Craig, etc) before they could get approval.  One of the people I talked to didn't know this until all her info had been submitted to insurance and they denied her.  I'm not sure about the other lady.  Now, I know that all policies are different but I was wondering if anyone could tell me if they had to do this too even though nothing was mentioned about it in their policy?     Thanks! Donna F.  :-)