Sounds like you have a well oiled machine that you are running, well done!!

However, this was in a “depression” Houston “Oil” market in 1982-3. 

My husband has a w2 position in the oil and gas industry.

Another option is the original paint was oil based and you are using latex. 

I am parts of groups where people invested in coffee, oil and gas, ATM machines etc. because they were chasing the depreciation components (especially back when there was 100% depreciation), they got all that depreciation but in some instances the funds took a turn for the worse and not only did they lose their investment they also owed money due back to the IRS for depreciation recapture where they took too much depreciation.

Units in the area usually heat with gas or oil. 

As someone who worked at a ford motor plant, and bought standard oil gasoline at shell, and purchased goods from Macy's, and groceries from a large grocer - it made sense for this individual to invest a portion of his/her earnings into these respective companies as they were a consumer - so by spending their dollars on the companies products if they were a small share holder they would be benefiting in the overall financial health of these companies. 

So buy a house where someone ran an oil change business in the backyard, you get to pay to clean that up. 

They really know what theyre doing and are a multi million dollar REIG very well established, well oiled deal flow.

How long has the home been oil market and how many (if any) price drops.Keep in your back pocket that, once under contract,  you plan to go back to seller and ask for a repair concession.