An arrowmaker would measure you from the deepest part of the nock to right behind the head. Then add for broadhead clearance.
To get the most accurate draw length, I would make the guy shoot a half a dozen arrows outside at a target. (This way we are dealing with a real draw length. If you stand in a shop, and draw a bow you can always draw it longer than your actual draw length.)
I would mark the last arrow right at the back of the shelf(side farthest away from you), then I would make you shoot that same arrow a few times, while I was watching the mark, and you are still shooting at the target to see how consistant your draw length was.
So yes, its measured at the shelf on the far side of the bow.
I don't know anybody, besides the corporate bow manufacturers, that use the AMO method.
Jim