I never see any reason to pay in advance for standard parking. You now pay when you enter the garage, not when you leave, so there is no real time savings.
As for preferred parking, while your lot is technically closer to the terminal, it is also uncovered. So when you get off your magical cruise and it is raining. Enjoy your up charge parking space. Also, why pay more to have your car bake in the sun and collect more sea spray than otherwise?