What is the function of a long sight bar? Why would I want to have it all the way out or all in? What I have read on this is seems to be a little conflicting so...

Next question. While getting to know my new sight I noticed a huge grouping difference between when the sight bar was all out vs. all in and can not figure out why. So I was hoping someone here could help me.
I'm using a Sure-Loc with a 9" bar. With a 3" spot on the target I dialed it in with the bar at mid point shooting at 9 yards. All arrows dead center. Now, with the bar all out I'm hitting at 8 oclock on the outside edge and at the 2 oclock edge with the bar all in. Am I missing something here? Is there a step I missed in the set up?
Thanks guys.

Bob

missing... no

give me a call Bob and I'll see if I can't talk you through it.

Ok thanks.
PM sent.

Bob

I was going to offer some assistance, but see that Javi has stepped in. I will defer to the master. Hope you get it sorted out.

Oops, forgot to finish up.
Yep everything got answered and I learned more than I ever expected to. Thanks again Mr. Cooper for all your help.

Bob