Ping pong is exactly what they did. All they had to do was call me and I would have met them along side the interstate on the first trip back and forth....I routinely watch my packages go from Staten Island, NY, to PA, back to a town in south Jersey, then to another town north of me before it's delivered. Kind of like back and forth to the edges to get to the middle.
I think it's the way their major/minor distribution sites are set up to get things to delivery sites in this case. In your case, they just played ping pong.