port length calculator seems vague

The description of the port calculator here seems a little vague. But, then again, I'm a total noob (notice the post-count?). It may be common-sense, so feel free to bash afterwards if these are really stupid questions/assumptions... 1) After running a scenario, the resulting output for port length must be manually multiplied by the port opening for net port volume, correct? 2) And that volume must be subtracted from the Vb that was previously entered for the port length calculation in order to achieve the true net volume of the enclosure, correct? It (obviously) makes a big difference and I want to make sure I'm not building a box incorrectly at inception. I usually do those kinds of things down the road due to construction incompetence. If the above is true, should/could the description be revised to help explain? If I'm the only who didn't "get it", I suppose it's not worth it anyway. I realize there are other factors involved in enclosure volume calculations, but they're pretty straight-forward to me. Any help is greatly appreciated.

Hi there.  The Vb entered into the port length calculator is net, meaning it is what is left after the volume of the driver, braces and port are subtracted.  So, you would ADD the volume occupied by the port (and the driver and your bracing) onto the value you entered in the port length calculator to calculate the total gross volume of the enclosure.Support the12volt.com

Well, I'm sure glad I asked...and you replied. Very clear. Thank you very much. Got a burnin' for some learnin'.