owwww
holding the ring at the mastheight value and dragging it to the shiplength value, which sets up the ring to take an AOB measurement... that process most be 'reset' every time you do it by first resetting the target range!
so I was trying to get the AOB at a range of 1000 m while the AOB finder was still set up for 1500 m
it had nothing to do with touching the attackdisc or anything, obviously.
sorted, I think
*wanders off to the idiot's corner and sits on a stool wearing a silly hat*
