String loops do not lengthen your drawlength, it actually shortens it. It changes your anchor point, making it further back, depending upon how long the loop is. (Usually you can figure roughly 3/8-3/4"
You can remedy this by using a shorter-shank release aid, or merely getting used to the new anchor point. I do not recommend changing drawlength unless absolutely necessary because you'll then break correct form by "reaching" forward to meet the string at anchor,and even tho you may "think" your anchor point is good, your form will actually be off. You can play with loop lengths a bit in conjunction with release length to find the best fit also. Good shooting, Pinwheel 12