This is all entertaining and interesting, but of little use to most folks typically outside metro and higher popullation areas.
Fact, regardless of who owns the "tank farm" or terminal, they get their supply from a variety of refineries. Refineries alternate all the time for various reasons. And refineries also get their base stocks for refining from a variety of sources.
Now, everyone in the general area is going to get their retail gas supply from one of several tank farms in the area. Again, it alternates. It is EXTREMELY rare for a branded station to have their own gas brand in the storage tanks.
What comes out of the nozzle when you fill your vehicle is rarely, if ever, the brand of gas of the brand of station. Now true, when fuel is loaded at the tank farm, additives per the customer standards are added into the fuel stream. I tanked fuel for several years and have seen all of this first hand. Ask any tanker yanker.
Now, regarding whether it is top tier or not, a large chunk of the country does not have top tier outlet conveniently near them. They are hardly ever, if ever, going to fill with top tier. They are not going to drive 40-50 miles or more to get access to top tier when they have a gas station 5 miles away near them. Yet, you see these fly over country vehicles lasting well into 200K miles with no fuel system issues or cats failing. Some will toss in some additive like Techron occasionally, but a lot of folks do nothing.