BCBS Fed Blue Question

Hi all, I had a question. I got approved for my surgery with my temp Cigna Insurance but had to undergo a 6 month waiting period. The six months also ended at the time of my open enrollment to get my permanent insurance for BCBS for federal employees. My procedure will be covered but my doctors office says they might require an additional letter from another doctor at least one year prior to the date of surgery for the insurance to cover it. I just wanted to see if this was correct or if anyone who has BCBS Fed knows of any waiting period? Thanks for any info! It’s been 7 months waiting already and I seriously am just ready to get this done and get healthy.