Port volume included in box

Cerwin Vega told me I needed a 2.5 cubic ft. box, with a 30 square inch port, 22.38 inches deep. Do I need 2.5 cubic feet enclosure, plus 671.40 cubic inches of port volume? Essentially, it would be 2.89 cu. ft. I really appreciate all input. Thanks.

 

I've read through some of the other threads on here. It looks like I DO add the volume to the cubic feet, just like bracing and speaker displacement. I have learned it is in the gross volume. You guys know your stuff. Hopefully, I'll build this one box, and be done. It's going into an FJ Cruiser. I actually thought about down firing it. More for protection than anything.