That's a problem you don't scan next package until you are at the next stop, you are wasting time. Also now FEG might be different, but at Express, GPS coordinates are recorded at scan time. You are supposed to SCAN and RELEASE(or get Sig) at the delivery location. Otherwise it can look like falsification(Scanning a package at 100Main street, then 5 minutes later releasing it at 500main street, could raise questions around here.)
But mostly you are wasting time going into the back the truck an extra time.
If you don't know your next stop you should be looking at your next few when picking your current package(assuming they are in order on the shelf)