Actually, I think the difference betw the two exercises is that on one of them (I can't exactly remember which), Cathe says DO NOT let the hips touch the floor. This made one of the exercises considerably harder than the other.
I could be mistaken that she said that, but I'm pretty sure she did, because I couldn't see a difference betw the two at first. Also, I wasn't feeling the exercise like Cathe a crew seemed to be.
Cathy