Jerry,
I'm not talking about just the same make, length, and spine arrows. I don't even have to change point weight! The bowyer admitted that would be a "long shot" (pardon the pun), even on two of his bows. I think there are just too many variables: center shot, differences in stored energy, strings, etc. I'm sure somebody with flawless form could probably detect a difference in tune, but I can get the same bare shaft to fly great out of either one and that's good enough for me.