You don't see the lack of mobility in those stats. He just couldn't run for a 1st if his life depended on it. Maybe the slowest QB to ever step on a college field (no hyperbole)
If you plug in the college rating for QBs ,the stat that seems to have the most weight is yds/ attp and not so much comp %.
10 for 20 (50%) for 200yds gets you a 134 rating
14 for 20 (70%) for 150yds gets you a 133 rating