I have never heard of this Entity before? Are they responsible for all the things before you get to OCS?
MEPS (or a military clinic for those who completed a physical there) reviews all physical exams to determine if an applicant meets commissioning standards, as well as basic special program requirements like eye sight and aviation.
If you don’t meet the basic commissioning and program requirements (e.g., SNA/Pilot), you are not eligible to apply—plain and simple.
If you are qualified and make it to OCS, that’s when NAMI, BUMED, etc., will conduct their screenings, such as the flight physical. This is where they can do things like anthro measurements, etc. If you have an approved N33 letter, it'll say "Defer to NAMI for final qualification for flight duty, etc." something along those lines.
The Marine Corps does NAMI physicals on the front end, that is all applicants are fully reviewed by NAMI before applying. The Navy does this on the back end at OCS, simply because there's way more applicants and it just doesn't make the most sense sending hundreds of kids to P-Cola.
MEPS does not perform special duty screenings.