I cannot quite understand your viewpoint - particularly the following statement.
"I think that the appearance of a big shift, after the downswing is due to the pivot way to the left where the center of mass has moved."
If the center of mass is already located well left of center at the end-backswing, then I cannot understand how one can still pivot far over to the left during the downswing. What part of Hogan's body is located well to the left of center at the end-backswing position, and how can one determine its mass relative to the total body mass?
How come the sequence you made approaching the top of backswing and the transition for the down swing got only one picture to show your point of view?
In my try with the capture, there are 188 frames of the same clip you did. From a few I made, I can see, before the club approaching the very top of the swing, the lower body already moved forward…or as VJ’s comment: “get the weight over to their left side soon enough in the downswing”
In the second row, the club was going even back and down while the lateral hip motion was already there.
The lateral move not only _________ but also ___________.
__________________
If you cannot take the shoulder down the clubshaft plane, you must take along some other path and add compensations - now, instead of one motion to remember, you wind up with at least two!