If you choose to have Shiptheory to download your sale before a pack task has been created, then the number of parcels on the shipment will always be 1. If Shiptheory downloads the sale with pack lines associated with it, then it will extract all the unique box numbers from the packing lines and count them to get the number of boxes.
In this example we have a Cin7 Pack with 5 pack lines spread across 3 boxes. Therefore the parcel countwill be 3.
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