If you are looking for a new doc, and haven't been able to get into your "first choice" try to do a little pre-interviewing before starting - in my world, this means to get the appointment through the corporate "appointment center" then, with the doctor's name in hand, start looking up their on-line profiles. Follow this with calling their location directly - this can be hard to do, but worthwhile, and ask to talk to their nurse or PA or respiratory therapist about how much MAC they treat. If they are not sure, they can always ask the doc. That is how I found my ID doc, who led me to the right pulmonologist.
Sue