I'll just say that the way you carry yourself professionally or not has a lot to do with any 'miss-understandings' in regard to your vendors 'wink-wink' pricing methodologies. 

See also https://www.biggerpockets.com/forums/80/topics/291751-what-macro-data-studie-should-biggerpockets-provide-to-investors Some places, Garner included, have some skewed numbers depending on your analysis methodology.

Our methodology is B or C properties in A, B or C areas (slight value add).Key indicators we look for in our deals are (CCR = 10% or higher.....

But be aware that there is a lot of push from some people to create a split tax roll in CA which would separate commercial property (which includes large multifamily) from residential property and strip prop 13 tax methodology from commercial properties. 

In other areas, other types of houses, different level of finishes, and different contractors, that wouldn't even get me paint and carpet.Spend some time reading other threads about how to estimate -- learning the methodology takes time and practice. 

For investors who bill back, what billing methodology do you use and what corresponding regulation do you have to follow (certified DS1 water system operator on staff, monthly sampling programs, annual CCRs, rate tarriffs, etc.)?

In reality it is entirely dependent on the methodology used to calculate the NOI.  

Nothing can, simply because every area is going to be different, every contractor is going to be different, pricing changes seasonally, material prices change monthly, there are different levels of contractors and quality, there are different levels of material and quality, etc.What the estimating book will give you:* A step-by-step methodology to learning how to walk a property and assess its condition and the repairs that are needed.* A step-by-step methodology to creating a scope of work for the renovation.* A step-by-step methodology for how to inspect various systems of the property to determine what is working and what is not.* A set of templates for the line items that will end up on your scope of work.* A ballpark range of pricing for each of those line items.

@Lucas Carl would you mind giving us a summary of your methodology? 

The methodology used in by Zillow and Trulia allows for counting some new construction as well as "flips".