Halflokum: As far as I know at UMich, there is no differentiation made between in state and out of state students. It is all about the audition. In my daughter's class there are two in state students out of 20 and that seems to be about what each class has.
Mommafrog: I do not have any specific statistics, but I do know that being deferred from an early audition is a positive thing. Many accepted students were deferred first. Very few seem to be accepted early and Michigan is very careful to leave openings through their March auditions. The year my daughter auditioned she was in the last group of March auditions that were still being considered for scholarship opportunity and a question was asked that many were concerned that they had already filled their class. We were assured that there were still spots open and my daughter was accepted the next week, others from the deferral group heard after that. I hope this helps, best of luck!!