the430miler, you fail.
There isn't a multitude of endurance work -compared to his mile times, the 5K times show relatively poor endurance.
Not to diminish the accomplishment, the times are fine, you WERE allstate, but from a 4:27 1600 you'd be expecting more like a 15:20-30 5K.
Given not running much before high school XC, the rapid progression in mile times during his freshman year just shows potential and carrying the prerequisite speed. Getting out and running slightly more than usual at all, without getting injured, is going to boost your times.
He didn't improve much after that. Continuing to run simply added on to a mediocre aerobic fitness afterwards, which never caught up to his mile times. You can't just blame that on "having more fast twitch fibers".
Those results just prove the inadequacy of the system. I've seen people where I live following the program, start to run, enjoy results as any running should provide, and level off and blame it on other things.
Then they go to college, find another program, and suddenly find themselves improving again.