Coupons only affect the accommodation fare of the reservation. The percentage-off coupon type can be configured to discount up to 100% of the accommodation fare. Basic fees, additional fees, and taxes will not be discounted.
In the case of a money-off coupon type, if the discount is greater than the base price, guests will see the following disclaimer before proceeding with booking the reservation with a money-off coupon: “The coupon value is higher than the booking fee. You won't be able to use the remaining balance.”