The location and/or movement "feel" of #3, is related to hinge type. Because the #3 "senses" the shaft on the angled plane but the back of the left hand (and therefore the grip unless you asjust your grip during the swing) maintains its relationship to the associated hinge. Therefore, only with angled hinging will #3 remain in one "feel" location, behind the shaft, because the clubface retains its relationship to the angled plane.
Which leads to why angled hinging is "best" for hitting and Horizontal hinging is best for swinging, but thats another story.