My class has 172 students so I wouldn't say 160 is a hard and fast rule. Also, I think during my cycle they accepted around 300 out of about 450-500 interviewees. It should come out to being about roughly 2/3 of the people who interview get accepted. They were still accepting people last cycle until end of January/beginning of February. After that, they interviews tended far more towards WL positions with a few scattered acceptances. After April they were all WL positions but they were interviewing for a long time - into May I believe. And they pulled a decent amount from the WL. One of my classmates was accepted less than a week before orientation week started. I interviewed in October last year and was given my II in August. It seems like a lot is happening in those months but realistically, there aren't a whole lot of interview groups, they are just very spread out. They usually have interviews every Friday - skipping some during holiday weeks, etc. And each interview group has anywhere from 10-20 applicants I believe. They are not large interview groups and they are only one day a week so it may seem like a lot of people are being accepted and the class is full but I'm sure they aren't even close to their class cap yet. They pace it out and with being neurotic premeds (of which I was one - but now I'm a neurotic med student) everyone is always concerned about whether or not they are interviewing for WL because their interview cycle is slower than most other schools but stay confident!
My roommate interviewed in December and I would bet that about half of my class interviewed in the spring!