George,
I've just tested this function (I never used before) and it works as it should. For each magnifying step the aircraft tried do "escape" but the picture was shifted right to the centre each time again.
BUT, after testing it again after restarting and reconnecting FSX I got the same phenomena as you did. After closing ADE, rebooting, connecting and locking it again, it was okay like in my first attempt.
Hmm, some additional observations: When closing FSX while having ADE centred to the plane in maximum amplification, the picture obviously jumped to nowhere (I just got the background colour). Center on ARP did not help but bringing the airport in sight and only repeating the command was successful, finally.