it just must be how fedex works. we've noticed that on our street, we'll see fedex stop at house, deliver a package, leave, and a while later come back to deliver a package two doors down. same truck and same driver. i think they farm out quite a bit of work as well. our dog as going nuts barking so i looked out of my office, and saw some sketch ball dropping off a package. older guy, ragged looking, no uniform. i had no idea what it was about, so when i got up to look, the guy drove away in a busted truck with a magnetic fedex sign on it. as a poster earlier mentioned, it's just their logistics.
on another note, our standard mail carrier, (who was a super nice guy) was just arrested for blowing coke in the back of his truck, and stealing gift cards from the mail. had him on camera and everything.