T9X

I've been searching all over here and CA.com for vented box specs for my Mag. I've tried using the box calculator at subwoofertools.com and I keep coming up with ~73in^3 of port area. From reading around it seems like I should be closer to the low-mid 60s. Am I correct or should I just stick with the plans swt.com is giving me?

I'm using a vented baffle enclosure rather than aeroports so that doesn't help me too much.