I believe that when the military promoted officers to a particularly rank, the promotion board would establish a cut off point, a particular score, which someone would have to get to receive that next promotion. Now, to maintain racial balance, they were willing to overlook minute statistical differences, IIRC basically within the margin of error, in order to prevent under-promotion of minority groups.
This probably had no effect on the quality of the officer corps, and certainly made the Army appear like a good opportunity for young minorities.
With many universities (Michigan was one example, I know Virginia Law School is about the same) a black could get a fairly dismal (or at least unexceptional) standardized test score and still be admitted. We are talking about huge quantitative gaps between what it takes for blacks and whites to get into these schools.
People seem to think we need affirmative action so that blacks can get into certain schools, which is B.S. They will do just as well attending Grambling or any other all-black school; the point is that, like all young citizens, to succeed they need to stay out of trouble in high school then move on to a college or vocational school.
We have so many universities in this country that pretty much everybody could go to some college if they're not too picky. And this is at least the first step toward a nice, comfortable professional job. Going to a school of little prestige did not hurt Secretary Powell; it got him into a legitimate profession (Army officer corps through ROTC) and his stock went up from there...any young person wanting to improve their station in life could follow in his footsteps.