Dividing NNN for a subleased space

[Page Huyette]

I'm running numbers for a master lease of a mixed use building:  two commercial spaces and one apartment upstairs (Units A, B & C is the apartment).

Units A & C are leased. Unit B is vacant and I'd like to sublease it. It has 4 offices and a common space, shared kitchen and two bathrooms. When determining NNN for the eventual 4 tenants, should I divide the common SF into fourths and add it to their total office SF? This common space is exclusive to this unit only.

The goal is to account for the total building SF, I assume.  What happens, however, is it jacks up the rent for each space.

Also, I've been using a spreadsheet from BP in my analysis, and am getting stuck with the column entitled CAM PSF.  What does this mean?