Both kinds of counter come from the hip, rather than the shoulders. You'll find that world cup skiers don't really ca in freeskiing because they can get away with it. They're far from human. Though if you take some clips from their race runs you'll see a lot of counter. As for more freeski people such as Reilly and Paul, I see it as they're trying to make their turns look good. The kinds of turns that they like to do (I like to call them demo turns) are generally pretty long and often they're grinding towards the end. No matter how much counter you start with or try to keep throughout the turn you'll always lose it if you try to keep the turn for as long as they do.
As for fore-aft I've always been pretty central in my turns, and instead have focused a lot on counter, as it allows me to grip where I otherwise would not, such as icy steeps.
I've found that counter is more important for grip, and that fore-aft is more for bending the ski at specific points in the turn.
