The materials just don't add/subtract enough from it to make "affordable" housing make sense in any sense of the word for someone building for a profit.I think the bottom line is that there's just not going to be any affordable housing except for rentals unless the government builds it/subsidizes it, or the economic bottom falls out to where no one has any money anyway.

Are the down payment and mortgage payments then subtracted out from the final price once the house is sold?

This will depend heavily on your market but I'd say look at the 1 bed 1 bath apartments in your city and go off those numbers and subtract a good portion to account for the fact that people will be living together in the same house... unless of course they happen to be friends.

You also have to add capital improvements and subtract depreciation to get at your real adjusted cost basis. 

Something reasonable like $25-50 to cover time and costs.Send a text back explaining that the source of the issue is the forwarding address she gave you was bad and you will be subtracting the cost to send it to the new address. 

Debt service is subtracted from the NOI and is technically not included in the Operating expenses of a property.

From there, you will subtract all your expenses.  

So, if your annual rent is $100, then start with $75 and start subtracting your expenses. 

Each year you subtract 1 from the previous year's life expectancy factor to get your new required minimum distribution.Example: 40 years old, $100,000 account value.

Math- rent x .75 subtract PITI.