gopher97,
That is pretty much my story! Din't have a problem entering on AP. The key here is Status, if you are in status then I-94 expiry is meaningless. I know Bitterman tried very hard to renew his I-94 on expiry after applying for AOS, and they kicked him out of the INS office for wasting their time.
But there is a world of difference between a Tourist Visa and a F/H visa. Tourist visa holders are usually given entry rights for very limited periods of times, usually 6 months (which can be extended by another 6 months), but F1 visa holders can pretty much stay in this country for as long as they hold a valid I-20.
So the key again is Status, if you are in Status you are okay, if you are not, then you need to leave the country and give up your I-94.