@Jacob Lapp ideally you put your money in a stock, don’t look back until 2-10 years later where it’s multiplied many times over.

The issues come when you have many people per unit combined with turnover or even a rent increase then multiply that by several units and it becomes work to figure out the dates of residency, amount paid, etc. 

Many calculators screen scrape unsophisticated rates and just multiply across a band of occupancy estimates which can be pretty inaccurate.

Like a deferred payment but put an additional multiply on it?

Which is actually a bad idea as unfixed repairs multiply over time (especially water damage). 

Of the three Approaches to Value, if there are no exact comps with two houses on one  lot, as an Appraiser, I would probably give most weight to Income Approach; both the Gross Rent Multiplier and Direct Capitalization-hope this helps.

The 3rd column is used for expenses I might add later, or to add up expenses that will be multiplied (the identical bedrooms). 

So multiply the ARV (After Repaired Value) times 75%. 

Therefore the appraisal form, which is set by the Banks/Lenders are different than commercial property's, which typically place more weight on the income approach.The small residential income property appraisal report, address comparable rental data and breaks things down into items like value per bedrooms, value per gross building area, value per unit and gross rent multiplier, etc.

The electricity and water required to do a load of laundry multiplied by the number of Tenants per week will add up very quickly.