I just bought a Bowtech Vital Impact(Diamond "The Rock"). I got it home and i have shot about a hundred arrows through it. Since then i've changed two things. 1) I moved the set screw that controls the valley on it a half mark. 2) I added a string loop. My problem is that i have to aim 6-8 inches higher on the target so that i can hit my mark. Can anyone tell me why?