Sorry for the repeated posts, but I keep coming up with more to say.
The USAW & some coaches on here advocate a sort of "first pull, JUMP! & catch" method. Sorry if I'm oversimplifying. In that style, the "JUMP!" would tend towards a heels up/triple extension lift.
From the WCC, I get the feeling they are looking for less of a "jump" and more of a "PULL REALLY G'DAMN HARD!" which would encourage a dig your heels down and lean back style.
Does that make sense?
I keep playing with both methods. I find the USAW method really great for dumbbell cleans & snatches. Jump & Catch! Easy to teach and easy to do.
When I grab a barbell though, I find myself wanting to try and dig down in my heels more and not jump quite so much as pull hard.