5'4" spitfire volume

I have a 5'4 spitfire, love it! perfect board in HB. When I bought it I did my research and thought I wanted the 25.5 Volume range. Going off the website and others recommendations on the forum, I bought the 5'4 Im 5'6 and weight 145 lbs. 33 year old intermediate.
Now Im looking for a step-up board, thinking stealth, mini driver, hellrazor and looking for the same volume. Anyway long story short, I looked at my spit and it reads 27.7 L not 25.7L like the website reads it should. Which is correct?? I would assume the board is actually the correct reading. 5'4" x 19.25 x 2.25 27.7L

According to that maybe I should be looking at a 5'9 stealth instead of the 5'8, or even the 5'10?

Any good info for me anyone? Huntington Beach two board quiver to complement a 5'4 spitfire


Nev/chris any info on which number is correct for me?