Then please explain how crunch time really works, since obviously you have a better understanding of it than I do.
CT improves Defense.You gave 2 reasons who could possibly be linked to the improved defense of the opposite team. And another that is semi-linked to improved defense.
1. Rebounds...
2. Bad FG% , which could be caused by the opponents improved Defense.
3. (semi linked) His 14 foults could be a reduced foul count due to improved defense. Maybe if he didn't play CT he would have 20+ fouls.