The boolean field "coupon" is optional and should only be used in correcting invoices of the following types:
-
COMPLETE CORRECTING invoices with
"code": "CORRECTION_1" -
SIMPLIFIED CORRECTING invoices
This field is set to true when the merchant applies a discount to the customer, but the discount is not covered by the merchant — instead, it is later reimbursed by the manufacturer.
For example: a customer returns a defective product. The merchant applies a discount of €121 (100 + 21% VAT), and later receives a reimbursement of €100 net from the manufacturer. In this case, the corrective invoice would include "coupon": "true".
This indicates that the discount was funded by a third party (the manufacturer), and is not a commercial discount granted directly by the seller.