A Pendulum Tires Of Sedately Swinging

Over the fifteen years I've had my route, the boundaries have shifted slightly to the west (to take streets from an incompetent and slow carrier who went on to become a station manager) and then to the  east (same carrier, same reason), but the core of the route has remain unchanged. For fifteen years. Now, the Postal Service, has a computer, and they're using it to define the routes. Inexplicably, my route is shifting east and west simultaneously, while the middle is being given to other carriers. So, I'll be driving past the customers I've had for fifteen years to get from one end of  my route to the other. I'll be driving past the entrance to the school I've delivered to for ten years, but someone else will have to drive through the street that shows on the computer's map, but that was closed about seven years ago, to actually deliver their mail, perhaps with a catapult.