THANK YOU!! One arrow with a nicked vane was flying right every time!! I'd never thought of that one! Turns out the nick was actually the tip of a tear that was obviously catching wind. I have three arrows with nicked vanes, but the other two are susally in the group. Now I've numbered them all with a sharpie and shoot in order.

So now I'm grouping all to within a quarter and have robin hooded four arrows. NOT! Still have a few errant flyers, but I did reduce errants by marking that arrow.