I know we've all seen this.
I sent a package to a Buzzer near South Bend. I'm in Illinois. It went to one of the Chicago area centers, then Gary IN, then down to Indianapolis, then back up to South Bend, then to his town's post office. It added at least two days.
I had something coming to me from Atlanta. It went to three different Chicago area centers before coming down to my post office. Again it added two days. The address was perfect.
What the heck causes that to happen? Is it software, hardware, or people?