For a real estate case, purchase with mortgage, basic P=R-C structure;
Revenues: Rent revenue & increase in the estate value
Costs: Downpayment & cost of the invested capital.
Here, don't we need to calculate the opportunity cost too in the cost bucket? Since if you didn't invest this money but instead land it to a bank you'd have received an interest which you can't get when you buy the house. So should the opportunity cost be added to the costs?