Hmm, I have BC&BS and they cover my brand name Adderall (I know that isn’t your request, but it sounds like that’s the reason they’re denying you).
Have you just called to talk to a customer server person there? I know when I needed permission for something (in my case, it was the need for name brand), they had a process, but I had to keep calling to ensure it was in motion. It sounds to me like they are confused about what the request even is, since they keep mentioning name brand even though your request is for dosage beyond the FDA recommended dose. 80mg a day is pretty high, even higher then the recommended dose for narcolepsy, so there is going to be hoops to jump through because they don’t want to be sued over it.