Multi-unit Appraisal Formula Understanding

[Scott Michael Gross]

Hi BP Community- happy holidays! Was wondering if people could help clarify how to estimate the appraisal value of a multi-unit? I am looking at a 12 unit complex and I understand that it's potential income minus expenses and then divide by the cap rate.  However, what expenses are taken into consideration? It seems to be historical vacancies and repair costs but not property management, taxes, insurance, etc.  Also, if the units are rented, but the rent is lower than market value, which rent would be used in the income portion?  Any help is greatly appreciated!