This months zip codes all produced an ROI of 7%! 

Deals come to you.Here is what a credible website that ranks #1 on Google produces.

so they make their money regardless of what we produce.  

The main house tenant did not like the STR part(after they already agreed to it), after the renewal we made both STRs and it's one of our best income producers(on a % basis).There's quite a few areas for this-- Virginia Beach, Garner, Zebulon, Pooler, Georgetown.

It's used to determine the cost of producing a product or service, and is a key tool for businesses to remain competitive and profitable.

If it is way more work and maintenance but cash flowing the same as a smaller unit doesn't make sense, but since you say high maintenance high reward I'm guessing this is one of the best producing properties.  

Many so-called "income properties" don't produce nearly the kinds of returns we see advertised on the internet. 

On the other hand, you build wealth by having income producing assets.

A few quick items:Red flags / tips:- Seller not willing / able to produce a written lease.

The articles conclusions MAY be self serving - we need to look closely  to perceive any motivations for WHY the writer is producing the article.