I want to purchase properties all over the U.S. in specific areas that my wife and I calculate and predict high returns on with multi family units, apartments, duplexes, etc.

I bought the land for $180 per 1 lot (4 adjacent lots, making one big rectangle)I don’t think anyone is quibbling with your comps or predicted sale price.  

You need to be making predictions on a property by property basis of both cash flow and IRR.

You can't predict what the HOA fee will be next year, assessments and changes in rules. 

I'm planning to have ROI, rents, cashflow, expenses, debt service, repairs/maintenance, return on equity, appreciation (I think this works over the long-term, kind of hard to predict in the short term especially with what we've seen in the last few years, but I usually conservatively estimate this anyway at 2%) and return on equity.

And to date, not 1 of the naysayers and doompreachers has come onto BP to recant there "certainty" predictions that were SOOooo wrong. 

It is also hard to predict timing if mid-term rentals will extend.

Most call centers use a predictive dialer to gain efficencies so their callers don't have "lag time" between calls. 1000 records is too small to run on that platform.

So for me the main challenge is finding properties and predicting rehabs and maintenance costs while periodically reviewing my numbers to make sure I am hitting my conservative targets. 

On paper, it makes sense to use such a service to have a predictable cost allocation towards maintenance.