This seems to follow the general overall trend of lower cost areas winning at the expense of those with a high costs of living.

Your adjusted cost basis is the purchase price plus capitalized improvements minus depreciation. 

Then you subtract your expenses: (1) Fixed cost: property tax, STR insurance, utilities, landscaping, etc

I had an outstanding cost of $30k that I rolled into a cash refinance on our primary residence. 

A 100-year-old home with structural concerns could mean costly repairs, so get a thorough inspection, especially for foundation and floor issues.

You are presuming the "seller used the cheapest labor, cut corners and and used the cheapest materials."

If that is the case then that is considered cost of doing business and I would advise that should be calculated in your costs/returns you provide to the investor.IF you are referring to the investor who is the borrower - then I would have included that cost in the loan agreement.

I have written 29 loans this year and the average Cost vs Appraised ARV is 69.6%.

From a financial standpoint, the key is to ensure you're purchasing properties at a price low enough to make rehab costs and refinance achievable.

It helps estimate ARV, rehab costs, and potential returns and offers funding options.