I would think it would move the same amount of air but at different speeds depending on the port area. I could be wrong but with the same driver it should be the same.
same subs, same box, same port diameter, diffrent tuning. they will move the air at a diffrent speed and diffrent amount. depending on the excursion of the sub. at that given frequency. i think the one tuned highes will move the most air when going below its tuning frequency. wich also have to do with the impedance raise and less controll of the sub. but also the amount of air moved is diffrent from the speed the air is moving. wich will happen closest to the tuning freq. i could be wrong too.