I was operating under the assumption that you are human, and thus are bound by the physiological and psychological attributes of our species. [8D] This is a known phenomenon which has been studied in depth by all kinds of psychologists and vision scientists. It's the way our brains are wired. It's why optical illusions work.

You are shooting better probably because you are gaining confidence. You think centering the pin guard is helping you and it gives you a psychological boost. If so, that's fine. 99% of archery is mental.

But your pin IS centered. Again, assuming you're human.

jsasker, if the housing is small enough, you could do that. The size of the aiming circle is important. Too big and you won't focus in on a small enough spot. Too small and you might as well be shooting a pin. If you take the pin out of a lens and just use the hole, then you've discovered how they came up with the aiming circle reticle for scopes.