tibreaker,
A couple of things to understand.
1. AFOQT can only be taken 2x, before you would have to request a waiver.
2. It is not a superscore or best sitting situation.
~ It is the last score situation. In other words, it can be iffy to retake it if you do mediocre on the test because if you do worse on the 2nd shot, than it will be the 2nd score that they use for your board
3, There is a 6 month wait between the exams.
~ Most cadets take it for the 1st time in the early fall of their sophomore year. Thus, when you go up for the board it will most likely be only that 1st AFOQT you will have on the books and in that case they may go back to whatever is your best sitting SAT.
I know you are trying to figure out which ROTC program you want to join come next fall, but before you start weighing the AFOQT factor for SFT, also realize that right now nobody can predict the selection rate for SFT in 2018. There have been years as high as 93% and as low as 55% overall selection. It is better for you to talk to the AFROTC cadre at the SMC you plan to attend than researching around here.
~ SFT is a national selection board, but the rates vary from unit to unit, and so do the minimums. One det. could say historically, the avg. for their unit is 3.1 cgpa, 97 PFA and 64 Composite AFOQT, another could be higher or lower. Don't just assume that because the national avg is whatever, and if you fall a tad below or above that you are in or out because the biggest chunk of selection will be your CoCs ranking. Something right now you can not predict where you will be in 2018 when you try to decide whether you go AFROTC or A/NROTC.
Good luck