Sorry you just found out -- but 6 months of pre-op weight loss monitoring is very, very common. A lot of people begin this process by calling their insurance company first to find out the requirements, and all of the surgeon's in my area ask for your insurance information at the information session or before the first visit. You might want to call your insurance company and find out exactly what is covered, how much you'll pay out of pocket, etc.. That way you can be sure you have followed all of the rules -- like most also require a pysch eval too.
Your insurance benefit book will have some of the info, so check that before you call. If you look through the boards, you'll see several insurance-related posts. I've been reading them all, so I can make sure I've jumped through all of the necessary insurance hoops!
Good luck!