Alan
Sorry Alan, my comment was meant to be taken with a bit of Humour. Something you must be short of
So since you have asked for a contribution from myself. Here it is. In real practical terms it wont really be noticed if you zero at the difference between 100 yards or 100 metres even when you then use that zero as a reference point to shoot at extended practical deer shooting ranges. An important note on that front is to try these various intended ranges on paper before ever shooting at animals.