Automatic Promotional codes work the same as discount codes.
Automatic Promotional Codes: Some promotional codes are automatically applied to the order during the check out process. If this is the case, the promotional discount will automatically be applied to qualified orders. Customers will see the list of discounts applied to the order on the check out page and on the email confirmation.
Note - Return Value: The refund value for each item return will be reduced to reflect value of free gift or discount.