Can somebody verify my sub enclosure measurements?

I'm building a box for a JL 12w3v2-D2 and I just wanted somebody to double check my math before I started cutting. I will be using 3/4" MDF with a double thick front panel.

According to JL's website the 12w3v2-D2 in a sealed enclosure requires 1.25 cu/ft. (23x14x10).

I'd like to build my box in the dimension of 16(high) x 16(wide) x 8.5(deep)

According to Crutchfield's website, to obtain volume, you multiply (height x width x depth) then divide by 1728.

This is where I got my measurements from:

(16 x 16 x (X)) / 1728 = 1.25

256(X) / 1728 = 1.25

256(X) = 2160

X = 8.4375

Inputs?