That book -- "The Book on Estimating Rehab Costs" -- lays out a methodology for inspecting a house, creating a Scope of Work (SOW) and then turning that SOW into a renovation estimate.I included a summary of the second book in the estimating chapter of the first book.  

This methodology will allow The Company the opportunity to evaluate the profitability of each property with each bid on the property.

Is it ancient?

I would like to expand my area, but I'm not as well versed outside the 2-3 areas I've focused on.So, I continue my search for the right methodology for my area. 

About half the floor was covered in ancient tile. 

I haven't looked at the neighborhood but from what you were telling me earlier I'd give the income approach at least 80% of the weight and sales comp 10-15%, with replacement costs rounding in around 5%.In the end though If I recall correctly you're looking to refi anyway so a lender is going to use their own methodology.

Take an ancient home, strip the aluminum, re-cycle it and offset the cost of the hardboard siding.

Just be careful of the MVP/Lean Startup methodology when interacting with the FCRA.

Is Ken's methodology incorrect since Grant said NMD doesn't work?

An engineering-based study is the IRS' preferred methodology.