Looking at that link for the angle cosine indicator (ACI) it appears to indicate that at a vertical angle you should range the target at only 25% of the true distance!?
So going back to the Anston target (almost vertical 15yrds) I would have to use an aimpoint for 3.5 yards.
I have no idea where that would be?
But I suppose I should find out!
Anschutz 2013 MEC1 .22LR
Miroku 3800 12bore