And on the line "total due from borrower" it appears the taxes have been added in and not subtracted.

I typically subtract 3%, of the ARV.

I'm guessing they try to subtract the deposit and probably run up the utilities.

Using the above example and subtracting 7% realtor commissions, your equity gain will be:$587,090 x (1-7%) - $460,000 ≈ $85,994.Your total gain, including cash flow, will be: $85,994 + $115,000 ≈ $200,994This is still way better than a CD.So, I do not agree with your comments.

To figure out if you can build a 500 sq ft addition, you will have to do the following: take the lot area, subtract the required setbacks, multiply that remaining area (called the Buildable Area) by 3 (because that's the FAR for R2 zones in LA City), and then subtract the area of your house and ADU.

The gain is calculated by subtracting the purchase price and any eligible costs (improvements, fees, permits, etc.) from the selling price.In your case, if you sell the vacant lot for $100k and your total investment is $100k, it seems like you might not have a capital gain.

Just subtract whatever % you have in current liens from 70% and that will tell you the potential about you can borrow.

Subtract all of that from the eventual selling price.

The only significant difference would be if I subtracted my primary residence from the equation. 

Then with what you have left subtract 10-12% for costs associated with getting a property.