Gentlemen,
Draw length measurement is for the length of your arrow, you pull the arrow so the head touches your fingers or the front of your arrow rest which are at or near the back of the bow so draw length is measured to the back of the bow. Because brace height is regularly measured sing the fistmele it is measured from the belly. This applies to primitive/traditional type equipment.
Having said that I believe the AMO or whatever they call themselves these days has different ideas with regard to draw length, but they are a manufacturing organisation who look for ways that manufacturers of widely differently shaped equipment may apply the same set of rules, not necesarily what is logical. I believe they measure draw length from the belly or a point on the back of the grip and add 1.5 or is it 1.25 inches, which is all well and good except for the bows whose grip/riser area is greater than this and the measurement ends up somewhere along the side of the bow.
Craig.