When you add a loop it is going to change your draw length and anchors.You need to shorten the draw length of the bow when adding the loop,then the anchors will need to be slightly up to get the anchors back to where you like.

IF YOU DON'T,the draw hand will be coming back to far making a solid anchor harder to achieve,assuming you were right to begin with.This will also cause your elbow to have a tendancy to over rotate.