I'm away to Portugal for the weekend but when I looked at parking charges for 3 days it is cheaper for me to get a taxi from the city to the airport and back.
That makes absolutely no sense.
Even pre-booked parking is more than the taxis. And no doubt they'd want to charge for four days despite being away for less than 72 hours (departure Thursday 20:10 arriving back Sunday 19:45 but then additional time waiting for departure and queuing for customs upon arrival).
No way to run a business. I don't care if the car park is full, if there was a bigger car park and lower charges they'd make more profit.