Martee - perhaps another way to visualize what is happening is to think of the triangle that is formed by 1) the ground 2) the shaft 3) a line that traces the underside of the arms at address.
as viewed from down the line.
'THE' plane is actually the line, the side of the triangle, that traces the underside of the arms. When you swing your 'hands', the pressure points, they move up and down that line (see 10-13-D).
If you have zero #3 accumulator, the clubshaft very nearly does stay on that plane.
However if you have some #3 accumulator, the clubshaft must be 'thrown out' from that plane.
Hence Ted's statement, the clubshaft MUST leave the plane. That throw 'out' is due to the pivot.
So when tracing, it can be quite useful to trace your hands along what is basically your toe line.
The "pipeline".
Annika does this quite well.
I hope this helps.
I need to think on this for awhile. But what I understood Ted's post was coming from the shaft rotates around the sweet spot, thus the shaft must move off plane. The plane under discussion is the Sweet Spot Plane and the fact that this rotation (some can be contribute due to the swivel) requires the club shaft to move off the Inclined Plane and toward the Sweet Spot Plane.
A Swinger- because of the location of pp3- moves the shaft and sweetspot on the same plane until release. The shaft stresses to seek the sweetspot plane into impact as acc3 rolls to square the face.
A Hitter because of its location of pp3- behind the shaft and the beginning of the sweetspot line to the clubface- drives the sweetspot plane onto the ball.
Swing educated hands- pp3- and all takes care of itself.