Would like to utilize the BRRR method for future properties, but would like to get a better understating.

The importance of location cannot be understated.  

Those expenses may be understated, and you need to walk the units, inspect the leases, rent roll and paperwork etc before you think too much about winning the deal. 

Do not try to broker it unless you have the proper licensure if required under state law.

However, this may understate the return on investment If the note is paid off early, if principal payment reductions are made, or if the note has a balloon.

I ask the owners to tell me about the rents and as im writing down the rents of each unit and doing the math, they were actually understating the income the apartments were making. then since they lived at the property they had not even counted the future income from renting their own apt out which had the best updates since they lived there.

They overstate their value in a deal, understate their expenses, overstate the rental market, etc -- the real deals appear when you've run conservative numbers over and over again, and it still looks promising.

I would likely understate the return of the rental house).Cheers...

My taxes and insurance weren't quite as high as what you have, but I can so very clearly tell you that you have completely under stated the maintenance cost.

That is correct that single family homes (operated as a single unit) are exempt from rent control under state law (Costa-Hawkins).