You just need a good system to track your expenses. that should be enough no matter where you pay the expenses with. 

It definitely helped to put me on the right track.

That is $63 per door on a small multi, and once they refinance that loan, they will be able to get all of that cash flow back!

Track expenses and income separately, as well as your time.

What it allows for is a No PMI loan with zero out of pocket for a owner occupied home up to a 4 unit multi family.  

And how are you tracking that activity?

I also think that those "outside factors you have no control over" that contribute to a neighborhood improving have been a guessing game, but are actually able to be tracked because of advances in technology over the past couple of years. 

For instance, if you are looking for an owner occupied multi family find an agent that has gone through the process with a client and been through the different aspects that are unique to buying that kind of property.

Weekly farmer's market, multiple LARGE cultural festivals, a sufficient music scene draw, some minor league sports arenas (Hockey, Basketball), and a flourishing LGBTQ+ community to boot.   

The few multi families that are out there on the MLS just don't seem to hit the right numbers.