One of the FT guys will be along to give you a proper answer. I think when you are shooting using a 56mm front objective lens you need to use high mounts to get clearance of the front of the scope.
You then need a higher cheekpiece to line up the eye with the higher mounts/scope.
Generally using higher mounts means that the holdover ( or dialling ) is less at longer distances than your zero. So that can mean the ranging at longer ranges is less critical.
The payback is that you then normally get more dialling to do at the close targets.
Anyway ... like I said a proper shooter will explain better but that's a nutshell's worth.