There is a chart that you can use to determine how many inches equals the number gallons is in a tank .You charge the tenants up front for the oil in the tank when they sign the lease , when they leave , you measure the tank and reimburse them for oil in the tank , as long as there are no other issues with the security deposit .

It's also important to note that not all installers measure the same.

They could try to make the case that they are tenants one way or another and given this is under Oakland measure EE, this could turn into a pricey time consuming process and result in an eviction.I'm looking for advice on if anyone else has dealt with a similar experience.

I appreciate your predicament.I was just watching one of Peter Harris' latest video posts on YouTube ("Ugly Side of Commercial Real Estate") which has some good advice.But, in a nutshell, it is simply a measure of what you are comfortable with mentally, and skilled with in closing the deal.

The higher the mark up, the more the discount.PRO TIP #10- Another thing to look for is PRO SAVINGS OF THE WEEK under home depot.com click on the pro site on the left hand side, we always have a special online for the week.PRO TIP #11- Eagleview, Real simple, A satellite measures your roof. 

San Jose City Council will meet next week to vote on additional rent control measures, including changing the current 5% rent cap to an inflation based index.

Cashflow (proforma cashflow to guide your underwriting in a value add deal) should be the only measuring stick for this deal.To your potential investment, underwrite the deal like a typical value add deal, if you haven't already, and then ensure you can improve the building(s) on budget and can raise rents to market.As for mixed use, their desirable by many.

What I'm looking to learn from some of you experts is, what calculations/measures should I use to calculate ROI on potential rental investments?

Search online for several other models, then tailor them to suit your needs and interests.What gets measured, gets managed.

As others mentioned IRR measures the return on an investment over its complete life; purchase, operation and sale.