How you turn your shoulders without moving your bow arm, your neck and head posture will effect your DL(as long as you anchor to the same spot like your middle finger in the corner of your mouth)....as well as your left arm elbow Position, and hand position on your grip....ill bet you could change a few things and have your Draw length all over the place(longer, shorter)....just depends on the person...as long as you are comfortable and shooting accurate no worries.

what im saying is that a little bit in all these areas can add up to alot....nothing is really too suprising in trad archery[8D]