I never put those on unless customers specifically ask me to. In this case, we didn't install it (for just that reason). We shot with the index vane up, down and out. Nothing changed. I'm starting to wonder if it might be the bow. I spoke with another fellow who is pretty good at tuning himself, he said he has fiddled with no less than THREE of these bows...and not a single one gave him anything but about a one inch high tear...which is what I got....beats me.....