This ensures proper accounting, simplifies tax reporting, and provides an accurate overview of your property's financial performance.

I posted the definition of ADU to simplify this.

But their proposal was 20% revenue share to "simplify the situation" after I mentioned base rent.

Of course, I'm simplifying things because the process is complex and drawn out.

I think your idea of simplifying is a good one.

Let's do a very simple, reduced example to illustrate how it works:Let's say the cost of the entire debt service (loan) = $1000/moLet's also assume your rental income from all of the units also = $1000/moYou divide the rental income / debt service (aka DSCR): $1000/$1000 = 1.00Most lenders like to see a DSCR ratio of 1.20 or better, meaning for every $1000/mo in your debt service, you are getting $1200/mo in rental income.Again, the example is simplified to illustrate how it works.There are lenders that do loans with a DSCR ratio of < 1.00, or even no DSCR, but there is always a trade off for those types of products - typically a higher interest rate. 

Also, I've heard from trusted sources the @David Toupin has one that is even more simplified than Mikes. 

I know some people say not to use cap rates for analysis, but I feel is simplifies the math substantially. 

Just pick the one that looks best to you for your style of operating.https://www.amazon.com/Organizer-Envelopes-Simplifies-Preparation-PocketCPA/dp/B07MPNMGHS

If you were you, I would hire a broker to look at a couple of reinvestment options, ask the broker to build a simplified spreadsheet model to compare the returns of the three investments (the two new one and the existing).