[HungryBear]

Take your RIGHT Shoulder as 'flat back' toward the Plane as you can. The LEFT Shoulder will then respond exactly as it should.

Thanks, BUT...
I am now/still confuses. I will try and rephrase my question with the concerns it creates. I do believe that I (that is only me at this point but I suspect many more of "us") get our left shoulder higher than we should, i.e. up under our chin, to facilitate a longer sholder turn but then the right sholder is allowed to "open up". All sorts of bad things may happen because coming down the left shoulder has to drop back into position or the left arm is now 3-4 inches shorter than at impact fix, the right shoulder has to restore its proper position on the way down and that (although in appearance) coordinated with the down plane shoulder turn isn't. I think (data limited to some video clips) the REALY FINE ball strikers, if you said at the top of your backswing, drop the club, stand up straight and face front without moving your shoulders, their shoulders would be like at address. I think (same caveat) the average guy-read duffer- would wind up with the left shoulder pulled way up and forward and the right shoulder back and open. If I am right then the back swing of the arms stops as the left arm meets the chest. To say it another way, If I lay a dowel across my chest at address and turn with the dowel the max shoulder turn should be with each shoulder holding its relation to the dowel at the top. Not with the left shoulder pulled up and towards the dowel and the right pulled back from the dowel. This is a very important question!