Isn't your point that you choose the edge angle needed to do whatever maneuver you have undertaken ? You establish the relation ship of CM to balance on that edge angle and this will make directional movements more effective and takes advantage of a higher efficiency of movement and energy used to complete them
Think of it this way: if you want to change the location/orientation of your CM when skiing you cannot just say "I'm going to move my CM over here" and just plop it down someplace; you have to make movements that act on your CM to change it's location. These movements usually originate at your feet, and will affect turn shape and balance point. If they do not affect turn shape, you're no longer in balance, and risking losing the ability to properly carve the turn.
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