Something rings the bell for me
I was stupidly metering focus distance from lens front, while it as you mentioned, from this mark many cameras have on the body.
Stupid me
Easy mistake. You are thinking logically, but not the same logic/standards used by those that mark lens barrels!
What Ian Grant just posted shows the same logic! I am sure the lens is not marked this way, but this ad brags that their lens focuses down to 41/2 inches from the front element.