You have a good point...The information I got in July 2007 about BAHA came from my audiologist during a discussion on Medicare and hearing aids, but he hasn't seen another AN patient besides me. Specifically, he said Medicare wouldn't cover the BAHA. But the surgery for the post implant is another story I think, as that would be covered by Medicare in any necessary surgery. I'd sure get the BAHA implant at the same time as the surgery. A surgeon sets this up at the same time and surely gives credence to the idea of necessity; so, denial of benefits would be more difficult.
I googled the two words BAHA Medicare and came up with the answer about the device. Check it out. BAHA is not in the same category as a hearing aid, that is the exception. I'd imagine some other aid developers will get into this also, in future.
I think it is too bad that regular hearing aids are not allowed for serious hearing loss. Too many older people lose out on life from poor hearing.