Sorry @LoveTheBard had to repost and ran out of time so did the … thing on previous post. Wanted to be more clear. Likely repeating what you said, but here it is again if so!
NMF half tuition (about 26K) is automatic if you are admitted and are a National Merit Finalist, and declare USC as #1 choice with NMS Corporation by May 1st. A Presidential is also half tuition, so this can cause confusion.
Acceptances (for scholarship recipients only) with invites to interview for Presidential and other scholarships come out in late Jan/early Feb, before the NMF results roll around. By the time the interviews happen in later Feb/March, students may know if they are NMF at that point. If a student is invited to interview for Presidential and then finds out they are also a NMF, they think they don’t need to show up for the interview for the Presidential because they know they get the same 1/2 tuition guaranteed by being a NMF. But a student should interview because there is a chance the Presidential scholarship is bumped up to the next level.
Another scenario is a student may get admitted in the regular cycle, be an NMF, then declare USC as #1 choice with NM Corporation by May 1st to get the 1/2 tuition scholarship. (Not half COA). In this example, that student would not have been invited to interview.
Using older figures (which are likely close because scholarship numbers haven’t change significantly), 800 students are invited to interview for Presidential (1/2 tuition - 200 total), and the full tuition scholarships, Trustees -100 total, Mork - 10 total, Stamps - 5 total. The question remains how many NMF’s are admitted and if they are part of the Presidential figures as USC doesn’t disclose the figure for NMF admits.
So — you can receive the Presidential and then find out you are an NMF. Or you can be admitted in the late March decision cycle, be an NMF and get the same ½ tuition awarded. Scholarships do not stack.
This is still the best info out there on scholarships:
http://talk.collegeconfidential.com/university-southern-california/1597366-tips-insights-observations-and-scoop-on-uscs-top-merit-scholarships-p1.html