Just a heads up this will not be tax free, it will be a pro-rated exclusion.

That is an uncontrollable variable.

So Cap-X erodes away cash-flow, at a compounding rate over time.

While less than 10% of the mortgage industry offers 40-year mortgages, here's something to factor in: they often come in with a rate increase of 20-35 bps.Assume 35 bps.$300k mortgage at 7.25% (30-year): $2,046$300k mortgage at 7.6% (40-year): $1,996Technically, it lowers the monthly, but not by much once factoring in the rate adjustment.

I would say for most people, the 1st position heloc is no a good bet, especially if you have a 1st mortgage rate of less than 5%.Using this strategy with a 2nd position heloc can be just as powerful, so you can have your cake and eat it too!

Variable cost and CapEx are where I see most investors make errors on their Pro Forma.  

Here's a bit more in detail about how rates are calculated for DSCR loans:1.

I welcome and encourage anyone on the forum to chime in if I may have misrepresented anything, but this has been my mental model after spending countless hours running through different scenarios.I dont have a heloc personally but just curious are they all fixed rate / or are some of them variable when rates rise the interest rate rises or when rates fall the interest rates fall.   

However, our tenant turned out to be problematic—late payments, issues that led to an eviction, and additional repair costs before we could relist the property for sale.Now, after months of making mortgage payments out of pocket, we finally have an offer.

Reach out to a commercial mortgage broker.