The tenant has come to discern your strained financial situation and is seeking to take advantage of you.

The other 2 may be a little more discerning.

If you think about it, there is no real discernible dependence between gross rents (determined by market, location, and certain high-level house features) and operating expenses.The 50% calculation is a heuristic, meaning it gives a pretty accurate estimate in most cases.

There is no discernible dependency between gross rents (set by market) and expenses.

I fortunately did not get scammed and used my discernment to not participate in the claims and remarks he makes but did speak with him on the phone before he tried his same scheme that he uses with most people which is too smart/slick talk you into giving in a certain amount of money (after detailing you on what he has done, how people have schemed him blah blah) for some promises and then disappears.

Get to know your market and spend some effort discerning market cycles.

@Collin SmithYou are missing the most important number of all to be able to discern if you are offering to much... the ARV...

Putting that many  properties on the market would have some effect but without a better understanding of the portfolio it is pretty hard to discern if that is good or bad.  

My properties are in A locations but that shouldn't be used for properties in C and D locations but a calculator doesn't discern between them and is only a very basic tool.  

The reason is because it can be considered here say and the judge would have a hard time discerning who is telling the truth rather than looking at a hard physical document in writing.When a judge asks if you signed something make sure to be accurate with the answer.