I do have to say that every AA group and sponsor is different. It has been a few years since I went, but when I was going I was on Subs and my sponsor told me since it was an RX med so long as I took it exactly as prescribed I was clean and sober and that if it helped I should continue taking it until I really felt comfortable about coming off it (and in general the group mostly felt the same way and there were people on methadone maintanence as well in the group). Many groups do follow the "RXs don't count as using if you are honest with your doctor and use the medication as prescribed.:
I'm not even a big fan of AA and don't think it alone helps many opioid addicts. I'm just trying to be fair though.