Trying to determine this figure for my properties so I know when its safe to skim off the excess for reinvesting. 

Cash from a cash-out refinance may be taxed when a distribution is in excess of your basis (ie, You put $100k into a $1m syndication to purchase a $10m property.

The only way around it is to put properties in excess of 3 under an LLC. 

So strategically, as the second mortgagor, it is only likely to foreclose on a home if there will be money left in excess of the first mortgage.

I would think most people can get above a 6% return investing it elsewhere hence I think it makes sense to keep your mortgage as is, reinvest the money into another asset that provides cash flow in excess of 6% and use that cash flow to support your higher mortgage payment. 

That way whenever you have excess money, you can pay down the HELOC but still work to buy the property now. 

In most instances, you likely want to get a cost segregation study.I would argue that maybe the only instance that you wouldn't get the cost segregation study is if your losses already bring you to a low tax bracket.I.E. you are making $100,000 and your STR losses without a cost segregation study are like $60,000.That would bring your taxable income to $40,000(or even less when you factor in the standard deduciton).It would be okay paying 10% or 12% on that remaining $40,000 of income.The con is that if you did get the cost segregation study done, that you would have excess losses carried forward to 2024.

My background is accounting so it just seemed a little excessive but I don't have RE specific experience. 

Massive excessive government stimulus has consequences.  

One concern of carrying 2 policies on the same property is that most policies have “excess” clauses.