Inconsistent usage of not applicable/not present

[vr000m]

If they mean the same thing, then use it consistently. Else describe if there is a semantic distinction between the two somewhere in the document.

[alvestrand]

We should use "not present" when the attribute might appear at a later time, while "not applicable" means that it's not present and it never will be, because it can't be. We should review usage.