[Yoda]

Both the Low Point of the Stroke and the position of the Left Shoulder (Left Shoulder-to-Ball Radius) are established at Impact Fix (2-J-1). The geometry of the Stroke then demands that, absent special purposes, the Low Point remain fixed.

The Left Shoulder, however, is not fixed. Instead, it moves (from its Impact alignment) down and around its Axis (the spine). Having moved down during the Backstroke -- beginning, probably, with a return to Adjusted Address -- it must then move up on its return move to the Ball.

Meanwhile, both the Hands and the Clubhead proceed Down Plane to the bottom of their respective arcs (directly opposite the Left Shoulder).