After that, it's do your due diligence to make sure you have an accurate grasp of rental rates, occupancy, expenses... then dive in!  

If so, does $160/mo seem accurate?

Make sure you are doing the correct due diligence on your end and your numbers are accurate.

But, really...they are all right...you have zero to worry about if you are operating within the law and keeping accurate records. 

Stuff like that.....the calculator assumes that cap ex is a percentage over longer periods of time, but wont be accurate if you get slammed with buying a new roof 5 years into owning the place!

Even with perfectly accurate data on the project and excellent reasoning, outside factors like viruses and changing market predictions can throw a wrench in things.

@Hattie Dizmond  different parts of Irving fall under 3 different school districts - Irving ISD, Coppell ISD and Carrollton-Farmers Branch ISD so a blanket statement "generally poor quality of the schools, I would not purchase in Irving" is far from accurate in my opinion... not trying to pick a fight just saying :)  Coppell ISD annually ranks amongst the highest. 

Essentially you need to understand the ROI associated with real estate (and Ideally investing in general) and how cap rates, equity, appreciation, and liquidity all play different roles.   ..and when you advertise your properties be sure to quote the most accurate numbers you can.  

Also, really important you know accurant rental rates in the area as you don't want to get caught with revenue much less than planned.

I've been through a number of real estate transactions in NJ and @Jonathan Greene's depiction is accurate.