[whip]

because the hands aren't(shouldn't) be traveling down plane at impact, but rather up and in.

Say it ain't so Joe! This is not correct and goes against one of the key concepts of the golfing machine and a 3dimensional impact. The hands and clubhead move DOWN and OUT through an even past impact all the way to low point only then do they begin to move up even in the follow through the thrust direction is still down plane.