Does a school know how many LORs are expected?
For example, when 3 letters are required, but 4 are allowed (e.g. 2 PTs, 1 prof. are required and the 4th is non-specific), what happens if the first 3 incoming LORs do not include the 2nd required PT LOR? Does the school know that one more letter is expected, or do they start their evaluation on the 3 received LORs (which would from their perspective be "complete" in terms of the quantity of LORs, but would also be an inadequate selection, because it doesn't include 2 PTs)? This mostly applies to schools with rolling admission.
For example, when 3 letters are required, but 4 are allowed (e.g. 2 PTs, 1 prof. are required and the 4th is non-specific), what happens if the first 3 incoming LORs do not include the 2nd required PT LOR? Does the school know that one more letter is expected, or do they start their evaluation on the 3 received LORs (which would from their perspective be "complete" in terms of the quantity of LORs, but would also be an inadequate selection, because it doesn't include 2 PTs)? This mostly applies to schools with rolling admission.