I was wondering why it was SO beneficial to be in the first few batches of interviews and my state school's admission staff explained this to us.
Let's say 15 people interview on the first day and they decide they really liked 8 of those people. The 8 people who they felt were a good match for their school gain admission to the school, but it is not over for the other 7 students who didn't get picked. When they interview another 15 people next batch, the 7 who didn't get chosen the first time have their files re-examined in comparison to the 15 people who are interviewing in the second batch. This continues for the rest of the cycle. The files for the applicants interviewed early may be looked at 20 times, while someone with an interview towards the end may get 2 "chances" in a huge pool of applications.