Subtracting speaker and port displacement

When entering the value for VB in box parameters, do I need to deduct driver and port displacement  or does speakerboxlite do it for you? Another words, the box Value before subtracting port and speaker Displacement is 2.0 cubic feet and afterwards it’s 1.8. Do I need to enter 2.0 or 1.8 for VB? 

Did you mean that VB?

Here you have to type useful VB other words 1.8 cu.ft. All additions SBL will do instead of you. I.e. after you specify the useful volume, port dimensions, speaker displacements, and other on the tab "Box" you will see the box total volume in your case 2 cu.ft.

Yes VB. 

Hang, you’re confusing me a bit here... You said I would need to enter 1.8 from my hypothetical scenario (the volume after deducting speaker and port displace) and then you said SPL does all the calculation. Which one is it? 

I've updated my answer.