On the UMich page, it says:
"One Teacher Evaluation (The Common Application) or Academic Recommendation (Coalition Application) is required for all freshman applicants, preferably from an academic teacher. In addition, all freshman applicants must have their counselor or principal submit the School Report (The Common Application) or Counselor Recommendation (Coalition Application) for the application to be complete. Please select this link for application material deadline information.
Do not submit any extra documents unless specifically requested, as this may only delay your decision."
However, on the common app, UMich gives the option to add two teachers and two extra recommenders.
Does this mean they do not want any recommendations in addition to the one teacher rec and one counselor rec? Or do they mean another type of document? It sounds like their common app and website are conflicting.