[Mathew]

Would you not be able to closely approximate low point from fix rather than address since impact geometry is being simulated there?

I don't actually understand your question?

Regardless of Impact fix where your engineering your impact alignments and these alignments dictate how you are going to hit the ball....and how these alignments affect your axis tilt which dictates again how that left shoulder is going to move, where your shoulders are pointed....etc... the point is that left shoulder is going upwards and because of this fact, low point will still be prior to directly under the shoulder. If you create impact alignments at fix and actually produce them during a real stroke where you have placed the ball directly under the left shoulder as your impact - you are fractionally hitting the ball past low point....however for numerous reasons, I don't think it is very useful to tell people to actually do this ... but geometrically this must occur for that ball location... even with the fact that the left arm is getting 'closer' to the plane and thus extending the radius somewhat (fractionally) is not enough (nowhere near) to counteract to bring low point directly below the left shoulder.