Hello! I have read the U of M website answer that stated that only one letter of recommendation/teacher evaluation was required, but would sending two letters be in an applicant’s favor? Or would it weaken the application? Or does it not really make a difference either way? Thank you!
Bump!! 
The quantity of letters will neither help nor hurt you. However, if you send multiple letters, they will take the content of all of them into account. Therefore, if you have a great letter, but then also mediocre or even negative ones, they are not going to only consider the best one for your application simply because they only required one letter. In short, it could work either way depending on the content of the letters you submit.
Also, you do need to waive your right to read the letters, otherwise they will not trust what the letter writer wrote. You won’t get to view the letters first and then selectively choose the positive one(s) to submit.
^first paragraph - how do you know?
It’s just common knowledge that if you submit more letters than the minimum, as long as it is not an extreme amount, then all of them get taken into consideration.
However, I think for the common app, you do get to selectively choose which letters go to which schools.
You effectively said a negative letter wouldn’t be considered if their is a more favorable one. That is dangerous thinking.
I hope you are not either a current student or graduate from UMICH … if their (sic) is a more favorable one.
If the second letter would cover different aspect of you, then it would be good. They used to require 2 LoR but allow 4. My D actually submitted 4.
@wayneandgarth I did not say that. If you read what I said closely, I said that if there are negative ones, those won’t be thrown out of consideration.
My daughter was the ultimate brown-noser. She got recommendations from each teacher she thought would benefit her chances for LSA Microbiology. Her Chem teacher, her AP Bio teacher, her AP Calc teacher, and her AP English teacher.
Each could speak to a different core competency necessary for her desired degree. Two men, two women. A white lady, a hispanic lady, a Middle Eastern man, and a white man. Two young. Two older. My kiddo believed this showed her ability to work well with instructors from a variety of backgrounds…and that she could succeed in all subjects areas necessary for her degree.
Four letters of recommendation might seem excessive…but it worked like a charm. She was among the first notified of her early admission.
If you want great recommendations from teachers? Set up a time to talk to them about the letter. if the teacher doesn’t know you well, write them a little paper about your aspirations and why they are important to you. Give them a “cheat sheet” to pull ideas from. Act EARLY. Give your teachers TONS of time to write your recommendation letters. Don’t spring it on them at the last moment and expect it to be a decent letter. They have lives… LOL. Be respectful.