A Good Gauge for Timing and Stamina

I like the intensity. I mainly use mock exams to gauge my timing and stamina. However, there are mistakes in the answers. For example, Net Assignable Area for a single tenant floor includes the bathrooms, janitorial rooms, etc. because they are used soley by the single tenant. they are not part of the net assignable area , if they were also used by other tenants (multi-tenant Floors).