It has been about 15 years since I ran a shipping department for a large training company, so this information may no longer apply. However, back then, U.S. Post Office optical scanners would try to read address labels for automatic package routing. The scanners would look for zip codes in the bottom right portion of the address block. If phone numbers were placed at the bottom of the address label, the digits in the phone number could be incorrectly read by the optical scanners as the zip code and totally mis-route a package to the wrong state.
As I said, I have been out of the industry for a long time, so this may no longer be an issue, especially if everything is pre-barcoded by the original shipper. I also suspect that optical scanners are much more sophisticated today. However, it might be safer to put the phone number at the top of the label rather than down where a machine could misread it as a zip code.
As I said, I have been out of the industry for a long time, so this may no longer be an issue, especially if everything is pre-barcoded by the original shipper. I also suspect that optical scanners are much more sophisticated today. However, it might be safer to put the phone number at the top of the label rather than down where a machine could misread it as a zip code.