However, If that number is off by a few hundred a month, the single family residence goes from 15% CoC return to nearly 10-- and 12 is my cutoff.1- in your experience, how good are those estimator service numbers?

This is my first time trying to analyze an actual property so here are my numbers.Purchase price:60kCash to close: ~3k(Im not totally sure how much I will have to bring to this deal as of yet.. so here's just an estimate)Income;Monthly rent: $775Monthly Expenses;Mortgage: ~$300Property Tax:$95Insurance:$75Property Management: $75Vacancy(10%): $75Repairs(5%): $40Total Expenses:$660Cash flow :$115Cash on Cash Return : 21%Am I missing anything?

You also need a really good rehab estimate.

I might add that it is also in an area that i was not familiar with so I probably over estimated the ARV and over improved even if the market hadn't shifted. 

Better to have someone working on them than having them sit.That being said, I don't take multiple estimates for every job.  

Scott The Book on Flipping Houses, The Book on Estimating ReHab Costs http://www.biggerpockets.com/flippingbookDownload BP’s newest book here some good due diligence in Chapter 10.

I doubled this estimate for my calculations.  

From what I see on BP there aren't a ton of areas where my numbers are even feasible.Another equation I do for testing a property is rent - 30% (vac&main) - PITI (15 year note) = reasonable estimate of long term cash flow. 

Im not sure If it will get that high in 2 years but 340-350 is a reasonable estimate.  

If the repair costs is estimated by HUD then you probably should consider having someone else do the estimate.