Also welcome Joel! In my dealings with lubrication issues, my clients, ususally large manufacturers buy all their lube oil in bulk; this may be the same oil that’s used in your cart or truck. I teach a course in lubricant handling and storage, and contamination is the biggest source of lube oil problems, not additive separation.
A fast lube place will stock several standard oils for their lube special and the filling hose will measure out the right amount. The additives in the will stay in suspension, but of course, poor housekeping may allow dirt and water to get into the bulk tank.
Do I use bulk oil? No, since I decide what weight and brand of oil I want, and that is never available from the bulk tank.
CRUDE oil is shipped internationally with 0.5% BS&W, that is bottom sediment and water. That’s the internationally accepted way since it is too expensive to get all the water out. During the refinig process all these impurities get removed, and the final product (gasoline, lube oil, etc.) bear no resemblance to the original feed.
Countries that ship bulk lube oil base stock for blending will try to have it as clean as possible, but the blender needs to clean it up further(centrifuge, filter, etc) before formulating the final product before bottling.