No one ever told you that as soon as you make something fool proof, someone invents a better fool, eh? This fool managed to lower it. See attached (Safedock2.jpg). Gate A1 (right) lowered, Gate A2 not lowered.
Also, the display is fine right up until about 4' away, at which point the arrow part of the display snaps to the proper height as you describe. The othe 99% of the system stays put at the height I set it to.