Today I had to ship 6 boxes (same address, same size, same weight) of
items back to manufacturer. No order number, not coming from a
marketplace. I used UPS.com because they have a duplicate shipment
feature through their website. Shipstation really ...
'@ShipStation - all the same reasons the other people who commented have
mentioned. Custom orders not through a marketplace, Multi box shipments,
Exchanges, One order being divided into multiple shipments and going out
on different days, etc..