I'm going to disagree with the idea of canting the bow. I've been shooting too long and know that at hunting distances you just can't cant the bow far enough to make a 4-5" difference without really laying the bow over.

And I doubt that it would make any difference if the third axis was out of kilter because this sight doesn't have any adjustment for it anyway.

My guess is that the man just isn't executing his shots correctly from an elevated position.