"And why does it pitch up when selecting Flap 1 to Zero?"
I would hazard a guess it is to protect from overspeed especially on heavy aircraft. I know of an incident where a crew manually flying a departure followed the f/d and got an overspeed which led to an interesting few seconds of airbus logic defying logic!! One problem is that the VFE strip disappears as soon as the flaps are selected to 0, but there is still a danger of overspeed until the flap indicator indicates 0. Unfortunately I have seen that one happen myself.
