You are missing the fact that it needs to be zoned for an additional unit. 

They could put an addition on doubling the size of the house, and if every other house in the neighborhood is at $500k, it still wouldnt raise the value $100k.

We are planning to hold the property and add it to our management portfolio. 

The property consists of 4 structures - 2 duplexes, an SFR and 2 car garage, and has 3/4 of acre.Here is the link to my analysis using the BP calc assuming a $455,000 purchase price and below is quick summary.https://www.biggerpockets.com/calculators/shared/260799/874435c9-b77f-4f96-a3de-90be11c4cbbaThe asking price is $475,000, Assumed purchase $455,000.I've assumed $30,000 in repairs as a place holder (TBD)Current Rents total - $4,700 + an additional $75 in income from laundry machines _ According to listing broker.Taxes are $5,868 (verified)Insurance $4,500When factoring in other expenses - landscape maintenance, water, elec, vacancy, repairs, cap ex and PM I end up with $610 in cash flow.

We also bought out own personal property in June of 2017 which we have updated and finished the basement on to add an additional bedroom, bathroom, and family room.

If your primary is 600 sqft, I am not certain an 864 sqft additional structure would qualify as an ADU.

I have 10% cash to put down and can get a bank to cover 60% of the Value,  how does someone obtain the additional 30% from open market funds?

In addition, that lets them be in the driver's seat if you don't make payments. 

The current marketing campaign is my D4D list, in addition to Tax Delinquents, and High Equity.

(BTW this is in Ohio)ADDITIONALLY, he is saying that he has until March 30th to get back to me on the security deposit..............