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How do I offer domestic ShippingDiscount for my listing? Do I need to specify ApplyShippingDiscount as true in addition to my ShippingDiscountProfileID in my AddItem request?
The Item.ApplyShippingDiscount tag is an older tag, and it need not be specifid if you are sending in Item.ShippingDetails.ShippingDiscountProfileID.
If both tags are given in AddItem API, for example :
then the second one will override the first one and the discount profile for 131044014 will be used.