Firstly apologies to the poster, whose comment on another thread prompted this question - I am genuinely intrigued by this concept and didn't want to hi-jack his thread.
The post talks about having his rifle "zeroed" to shoot 1" high at 100m. Surely "Zeroing" high is not Zeroing at all? If a set up is Zeroed it means that the bullet hits dead on the aim point at the chosen distance.
May be the way my brain works but I see no point in "zeroing high" at say 100m and then having to aim off at 100m!! Why not Zero bang on at your choosen range and then aim off is your target is substantially closer or further away?