A loop does not change your anchor point - eye to peep, kisser to lip, nose to string, feather in mouth...etc.
It will change how far your hand lays on your face, and how far your drawing shoulder and elbow rotate.
Ok Rack, I should have said "
an anchor point"

You are correct the the other anchot points do not change only your release hand anchor point will change![&o]
As for the string loop and the nock thing...mine is directly behind my nock.