General question regarding running numbers for viable BRRRR opportunities in LA.

We are all told that the max allowable offer should not exceed 70% of the ARV less the construction costs.

I would like to know if LA investors (specifically those investing in single-family and duplex/triplex properties) are able to realistically find these deals.

As an xample - Let's say a 3-bedroom, 1.5 bath home in North Hollywood is listed on Zillow for $660,000. And comps show an ARV of $760,000. And let's say the rehab estimate is $45,000.

So this would mean that the max allowable offer is $487,000. ($760k x 70% minus $45,000.) 

I have a hard time believing that LA investors are finding and buying based on this example.

I would like to know if anyone in LA doing rehabs either to flip or as buy-and-hold investments are actually using this formula. Is anyone actually able to find sellers willing to sell at this discount?

OR are LA rehab investors typically doing deals and taking a smaller margin?

And a follow up question would be :

If my target investment property is a house-hack for myself, would I be well-served to ease off of the max offer of 70% of ARV?

If I'm able to make the number work to where my rents cover or almost cover my mortgage, AND I'm living in the house as well - should I be open to a deal doesn't meet the '70% of ARV' criteria?

any thoughts are greatly appreciated.