> "Here's another tidbit people don't understand. If the property has more than 4 units, the value of the property is determined almost entirely by the revenue it generates."

actually, that's pretty straightforwardly "income-based valuation", and it's logical because having more than 4 units means the property is primarily a business and not primarily a residence. businesses are valued by the income (i.e., profits) they generate. the sales comparison method (employing "comps") is primarily used with residences because the more accurate income-based valuation isn't available to residences, as non-income-generating assets. (the third valuation method is cost approach, which is used as a primary method of valuation in markets with low turnover/few comps, and in many tax assessment jurisdictions).