@midway 

It's a contributing balance item.

And it inflates the value of the rental if they're rounding up.

And by actual cost would a formula that accounts for the costs. So eg: THAT amounts to 1937. Just say that's what the real world cost is to the landlord. Mortgage is paid, Property taxes are paid. Maintenance etc. The landlord has accounted for profit. The landlord is making profit at 1937. Rounding up to 2000 is inflationary on the market locally. The extra 63 bucks is bloat. 

 But how does one determine the “profit”?  

You’ve got it backwards. Inflationary forces (like massive money printing, increases taxes/fees/regulations/etc. and restrictive zoning laws) drive up demand, increase costs, and suppress supply which drives up prices. The landlord is responding to market forces and should try to get whatever he can for his property.  His cut of the rent is not a fixed variable.