Only if you reduce the draw length of the bow to keep your anchor points the same. Adding a loop does not change the physical draw length of the bow at all. It will effect the percieved draw length though and if you go too long it could mess up your form negating any actual benifits you would be getting from shooting a loop in the first place.

In some cases people don't shoot too long a draw length on the bow, they use too long of a release and it puts the hand too far back to get good form and shoot consistantly. Most releases people use are designed to be shot off from the string.

Paul