Changing insurances??

I currently have BCBS of NJ PPO and am looking to switch to BCBS Federal at the beginning of the year(2008)  I was told that my current insurance requires a 6 mos. supervised diet and that BCBS FEP does not require it. Has anyone had either insurance that could comment? And also, will I have any problems switching insurances in the middle of the process? I have had my orientation seminar, bloodwork and Ab ultrasound but that is as far as I have gone. Meeting with surgeon today!