Anyone heard of applying chevron shingle oil to Douglas fir cladding/siding?

My local sawmill says he  applied  shingle oil to his house a couple times over the past 20 years and it’s still doing great.  What do you guys think? My local sawmill says he  applied  shingle oil to his house a couple times over the past 20 years and it’s still doing great.  What do you guys think?Read MoreGreenBuildingAdvisor