Frost on the Clothes Line

I don't know exactly how it happened but I ran out of chili powder AND pepper this week.  Got on-line to order more from Penzy's.  I put in my physical address on the first address line and on the second address line I put in my P.O. Box - the sequence requested by the Postal Service.  The software took only the physical address on the first line and blanked out the P.O. Box.  OK.  I reversed the order.  The software took the second line w/ the physical address this time and blanked out the P.O. Box again.  I put in only the P.O. Box and the order went through.  I e-mailed the company that their system wouldn't take both a physical address and a P.O. Box.  I got a quick response stating that this was a feature of their system in order to check a proper address was entered.  I thanked them for their response but suggested it was a software 'bug' more than a 'feature'.  P.O. Boxes have been around a lot longer than ordering on-line - you'd think companies could have figured out a good way of handling it by now.  I'm all for drone delivery when the only address you give is your GPS coordinates. (ha)