[MizunoJoe]

But "mentally constructing" is not one and the same as actually Thrusting from End .

I would note that in the text:

"At the top of the Backstroke – even at End (10-21-C) – mental construct a line form the #3 Pressure Point to the Aiming Point."

he specifically says "top", not "Top", which makes me think the mental straight line construction AND the thrust is at the top, even if it's the End, and not the Top. After all, you hardly have time to mentally construct anything once the DS is under way. Also, thrusting from the End would deflect the straight line effort to start from the Top automatically.

HOWEVER, you are absolutely right about plane shifts and the Aiming Point, because of the text on pg 202, in 10-23-B. Angled Line:

"From the Top-of-the-Straight-Line hand position the Hands take a nearly vertical path to the Plane of the Elbow Angle before they start their drive directly at and through the Aiming Point (2-J-3)."

I can't explain this apparent contradiction.