I have the following theory about what happens when OOS students drop out and it is based on the actual numbers at each school when the school starts. This is not knowing the real process but just looking at numbers and proportionate postings in threads along the way.
1. Schools are filling OOS students close to quota at the following (UTSW, Long which seems to be doing more than quota, McGovern, Tech, Baylor which does not need to meet 10%,) and exceptions to this are UTMB and A&M which dont admit to quota upfront.
2. The schools that do to quota decide whether they want to replace OOS dropouts with OOS drop outs - UTSW upto May 1st week, Long probably same but looks like McGovern has dropped that practice based on having only 9 people last year.
3. None of the TMDSAS schools (except Baylor) offer OOS admissions past May 15th. All of those seats are given to Texas residents who dont have any admissions.