When I applied to pharmacy school I had talked with many school representatives whether on the phone or in person or in online chats/meetings. I found out when I asked about "what happens when I designate more letters than your school requires?"
The majority of them (if not all) all said that it was okay if you sent extra letters (you would not be penalized) and that if they had time, they would read everything you sent, because it provides additional depth about your character.
A few schools said that they would randomly select letters (although they will not do that if you tell them specifically), but most of the time in practice, even these schools will peek at your other letters especially if you are a borderline applicant because they want to know more about you.
