Just saw tonight where I had seen these scopes and being used, it was on one of the Hunting programs on OLN. Kind of reminds me of a scope I had years ago, it was a Bushnell BDC "Bullet Drop Compensator".
Looks like all you have to do is dial it in at say 100 yards dead on, re-insert disc and then at a determind distance, 150,200,300,400,500 just change the dial and aim dead on. BULLS EYE. Just my idea of how it might work having not seen one and or read the instructions. That's the way the Bushnell worked for me.
Brian