If at the end of the offer period the current price per night is lower than you paid when you booked, you will receive the difference automatically as a cashback payment 72 hours after the end of the offer.
19 nights must be booked to reach the next discount level.
Every offer for a listing has five price levels and the price decreases as the number of nights booked by guests increases. The more nights that are booked the lower the price is for all bookings.