Here's how i think it works:
Shouldn't be any wait-list activity until around February, there are currently ~100 spots filled with ~75 on hold (and roughly equal partitions remaining for each of the branches), these spots will be filled by the end of January. The remaining spots will be filled (along with any voluntary drops or drops due to lack of medical or security clearance) in the order of the rankings of the wait-listed candidates (your board score out of 15). Most 15s got full acceptances. If you received a 14 you had a good chance, but you're not necessarily in. If you're a 14, you're going to get called up before those that received 13s, and likewise for 12s. Depending on how competitive it is for 13s (and how many drops there are), 12s may not get called up for a spot at all.
I was wait-listed last Friday (10 Oct Interviews) with a 12, so I almost certainly will not matriculate to USUHS (unless there's some miraculous surge of attrition this year compared to last). Sad times, but I gave it my best effort. Good luck to everyone else in cycle and Happy Thanksgiving.