So many flaws in this theory..Her role is minimal?  

I recently got pulled into an "as-is" deal to help out another agent, where the seller had agreed to a lower price and in exchange would not even want to do a $200 repair at this point - later the inspection discovered that an addition to the house had been built over the risers of the septic tanks.

As you've discovered, most people aren't that handy and the homes stay just as you left them, which makes your park look bad.

I am sure this is flawed.

What I discovered is that the 50 lowest-priced properties were producing 15% of my income but almost 50% of my work.

It was a few years later I discovered real estate investing.

These spreadsheets and systems ignore the reality of flawed people.

Really you need to discover what works and what does not work in your area and stick to it, people use rule of thumbs and guidelines but all these things vary regionally and are never set in stone.  

I have compared a few cities with Tulsa using realtor.com and zillow, and have found consisted quintiles of rentals available per capita(I know there are more available properties and this has flaws in comparison).

2018: Discovered Bigger Pockets through a combination of another blog and a friend who is a BP member actively executing his real estate plan.My goal is to, in the next 7 years, acquire enough cash flowing rental units to fully replace my and my wife's income (maybe with a little help from my pension).