This may be the salient determination of several "knocks" on the SS/aware loop.
If one does not know the position of a deflected control surface, and by extension the "actual" position of the SS, well.... "You climb", "I am climbing?"
"Climb, then..." "No, don't climb...." "Well, then, go down...." "He is climbing...:
"Someone should, we are at 4000 feet....." "Tire, Tire, Tire..." (Pull. Pull, PULL)
If PF, at his initial aft stick, then assumes his input is zeroed, he will think, "fine, oops, I need an aft stick..." Each time assuming his input is an isolated one, instead of "additive" (accumulative)..... This is affirmed due the inexplicable travel of the THS full up....
"The Airbus side stick system lacks the "position of the control surface feed back loop" to the pilot. We have no easy method to see how much control surface deflection is required to satisfy our side stick input. It is very useful for an experienced crew to know."