Why not save the money you would be throwing at the principal and invest that in your next deal? 

On top of $750 cashflow, are you also making more on the principal repayment? 

Now, in my dotage(I'm 44;) I look at the portfolio and can clearly see that the theoretically lower cap rate properties have been substantial outperformers over the years on the metric of cash flow- so I'm pruning the challenging(and capturing the principal appreciation, *wink wink*) to replace it with the chill. 

Ahh its like Principal and interest.

I noticed that when I calculated the numbers manually I could get the same NOI if I left out the monthly mortgage expenses of "principal & interest". 

Buying sub 150k SFR rentals is simply not that complicated.. use 50% of gross to 60% of gross rents for fixed costs back out your mortgage and that's your cash flow.. if you do a little better great but this will keep you out of trouble.. just like when my accountant wants me to over pay my quarterly estimates it keeps me from having penalties even though I don't really owe that much.. same principal over estimate and live with better results.. 

I pay an additinal 550 a month towards principal of my mortgage .

-If I cash out refinance, my payment goes up to $1,700 a month (5% interest rate), or about $1,200 a month after principal pay down and tax benefits and I get 110K cash out to set aside for more investing down the road (have significant cash reserves for that now though too).

Same principal as insurance.

so in essence a flooring line then when they are sold he signs them over in exchange for his principal and his return.. usually 15 to 18% interest on those.. got to choose the used car dealer wisely of course.. they have been known to fudge titles and your collateral has driven off without you getting paid.I also have a client.. they happen to own a few Toyota stores in Oregon but one of their business and I think it could be one of the largest on the west coast is they buy sub prime auto debt... you know the kind were they put the chip in the car and also a little do hicky that flash's when the payment is due  and then when they are 15 days late or some amount of time the car is disabled.. so they can use the chip to find it and its disabled and they can just go and repo it.when I was in Jackson MS I asked a used car dealer there that I met at my watering hole.. how the heck do you sell cars for a 100 down 100 a month .. he said  SON  my clients are born live and die all within in about a 10 mile square area here and the key is getting their mom's name and number.. we just drive around till we find it or call mom and get the whereabouts..