I just went through all kinds of headaches getting a resolution of being uninsured because of mis-applying my payment, refunding the check to the wrong "Walt Payne" etc. in Florida, and no, State Farm does not even do homeowner's in Florida.

Steven,First the idea of discounts is fairly misapplied in these realms.  

And those spinmeisters who create a lie by presenting this as something its not are far more dangerous and disruptive to our country than misspent taxes and misapplied tax credits.

I think some of the items you've identified are misapplied constraints when it comes to doing a good deal (such as sales tax and soil type).

I can't necessarily say that there is one set magical point for any given person.In regards to your second question, I would go to the opposite perspective and caution you to not misapply analysis either.

The rehab works appears to be been well done and this place is already rented and ready to go.Using the 50% rule, and this may be being misapplied by me, it appears to only be a decent purchase at $100k; based on goals: CoCR > 25%, TRIO < 5 yrs, Cap Rate > 6% at $100k it is right on the line of those goals.Financing through local commercial bank that I have worked with in the past, 5yr 20am @ 5.5% (might be between 5.0 and 5.5), assuming 20% down and about $5k in fees at closing.

This is not generally true, but often misapplied.  

It seems like if you feel the law is unfair, unjustified, or misapplied, there's a perfectly legal way to go about it - work to have the law changed.

Some of the regular go to books (like Kiyosaki) have good info but can be dangerous when misapplied or prematurely executed.

Because I think many people starting out intuitively understand the safety of cash purchases but misapply it to their small portfolio business.