Left undirected, the Hands go where the Right Shoulder goes.
In Start Up, that means "inside" the Line. But, the Hands have a choice . . .
And that choice, as the Right Shoulder rotates back -- toward the Plane -- is to point the Sweetspot at the Straight Plane Line.
From the Top, if the Right Shoulder rotates off the Plane -- "outside" the Line instead of toward the Ball -- then the Hands have no choice . . .
They must go along. Geometry -- however On Plane intentioned -- is no match for Off Plane Physics.
Fortunately, Educated Hands understand this phenomenon and control it.
Integrate the Start Down Waggle -- 3-F-5 per 8-7 and 12-3-0 / 7-- into your Pre-Shot Routine.
This is another level of understanding. Until now, Id thought of hands to pivot in regard to the backswing. The on plane move of the right shoulder in start down as hands to pivot too...............hmmmm.....of course.