Interesting. So in these cases compound peeps are effectively rear aperture sights. A peep sight in rifle shooting is a simple hole you view the foresight through, but an aperture sight usually refers to a much smaller hole which acts as a lens, like in a pinhole camera. This has the effect of focusing both the foresight and the target when normally it's not possible to have both in sharp focus. Do some rear peeps incorporate an actual lens rather than just the simple aperture?Some front sights with a lens need a peep to bring the target into better focus.
There are some archers and documents on the 'net that say that's exactly what you should do (Levi Morgan for example talks about setting his peep height differently depending on what ranges he'll be shooting). Then slight movements up and down when the front sight is at its extremes. Maybe because the eye is looking through the peep at a different angle at longer ranges, so the body of the peep obstructs the view of the sight ring?Sometimes the peep is not well positioned and the temptation is to move the draw hand to get a good view.