Since the thread is about gaining control from the top of the turn, what do you say we go back to that?
It's obvious some will never agree on turning methods. So what is your proposed method for slowing down and not smearing a carve? Personally I would think you would be forward on the ski and not have your outward leg run long. This could slow you down a little but would become a smeared carve easy. In order to reduce speed by any substantial amount wouldn't you have to smear it? I suppose you could carve up hill if it's wide enough but that doesn't make sense.
Do we have to slow down in order to gain control at the top of the turn?
No. However in some dialects (often spoken by ski instructors), "control" means means being in control of your turns and associated body positioning, AND keeping your speed low. To maintain control of speed in the sense of keeping it low, it is necessary to have control over you speed at the top of the turn. If you lost "control" somewhere at the bottom of the last turn, then you need to get it back at the top of this turn, and that includes the keeping your speed down part of control too.
For other dialects, control should not be lost, but if it is lost it needs to be gained ASAP (whether that includes maximizing speed, minimizing speed or anything in between).