Does anybody know the true purpose of the big "human-readable" zip #'s on our shipping labels? I have been a sorter for three years and have yet to figure out the true purpose of this bigger than the zip number. As a general rule we are supposed to use the zip code on the label. I use the zip code always with a few exceptions on those rare borderline towns that we rarely see. then I will look at the human readable to help me determine where it goes. Some sorters have a bad habit of using the big numbers to sort and they are mis-sorting alot. What I want to know is why the number is called "human readable" in the first place? While I feel like a robot at times while working, I am not, I'm human. So, why can't I use the "human-readable?"