its just a way of measuring and not a rule ,,,, ,for example if you draw 28 to the hand with a certain bow,, now add 2 inches depth to the handle for fun,, if you draw 28 inches to your hand,, the bow will be drawing that same arrow two more inches,, the limbs will be moving more,,etc,, yes you are still drawing 28 inches,to your hand, but that bow would now need a 30 inch arrow,, if you increased the handle depth another inch,, then the bow would need a 31 inch arrow to back of tip,, so the bow would be working harder again,, even though the measurement to your hand would not reflect that,, I was a professional bow maker for many years,, and if a client wanted the bow to be 58@28,, I would measure from the back of bow so there was no confusion,,that being said,, any way you want to measure your bow that works for you is great,,