One thing you really need to look at it that there really is no "late" application, for the most part, until the deadline has come and gone. Many schools are interviewing into late April these days and acceptances that late are very common. Why? It's the rolling admissions process.
When the MCAT was only given twice a year there were two floods of applications. One at the beginning, for those who took it in April, and one when the August scores were released. If you didn't take it by August... then you applied the next year. These days, applications literally are filed all the way through the process. Schools know there are late applicants and most of them have seats available until they stop interviewing. There are, of course, notable exceptions. Yet, lots of people are now taking the January MCAT, getting interviews in March and April, and getting spots.
A lot of people are under the misconception that you are applying for 150 vacant seats in July, but only 10 or 20 in March, so it's harder to get in. That's not necessarily true. Schools typically offer a certain number, or range, of people admissions each month. You are really only competing for the number of seats they intend to fill right then. They accept the ones they want and they waitlist the people that are ok while they wait for the best applicants from the next group to interview. People they don't want are just denied. If they have a particularly bad month of applicants that come through, they might pull some from the waitlist. Usually, though, there isn't a lot of waitlist movement until interviews are over.
The simple fact is that if you are a mediocre candidate in February, you have about the same chances as a mediocre candidate who applied in July. When interviews are over you'll be fighting each other for a chance to get off the waitlist.
There is one other thing that really deserves discussion, though. You can be a mediocre candidate and still get a spot by working for it. If you really want to go to a certain school, get off of your butt and visit them a couple of times during undergrad-- before the applications process takes off. If you have inadequacies (a less-than-stellar GPA, for example), talk to them about it before you ever apply. Meet representatives from the school and ask them ehat you need to do. Become a familiar name in their minds and you will be taken more seriously when your application finally arrives. chools may say they have an absolute cutoff of 3.2 for GPA, and if all you do is send in an app with your 3.1 showing they will throw your app straight into the waste basket. BUT, if you are on a first-name basis with couple of folks there at the school, you might just get a shot. There really are no absolutes! Rules are broken more often than you might imagine. But rules don't get broken for you if you just send in your app, sit back, and wait for something to happen.
Getting into medical school is hard. It's intended to be that way. But, when you work harder than anyone else you can also get results that are better than anyone else. Chances are that you will end up with someone in your class who has a 19 on his or her MCAT. How does that happen? They worked harder than anyone else to get in. Or, they could be sleeping with the dean... but that's another story..haha! Good luck!
