The process is pretty easy, and if it's branded as Phillips 66 it should be their "branded" additive added at the fuel terminal. I think it's required to be meeting the requirement. Currently there are some issues with getting enough additives, but I believe they have to note that they may not meet Top Tier requirements temporarily.
I think it's like a lot of places where they have a gas station brand and a different convenience store brand together. I'm pretty sure the gas station portion is considered a full station for that brand. I've seen combination Circle K/76, and around here even a Circle K/Valero/Burger King. I think they're supposed to meet the Top Tier requirement unless they clearly state that they're suspending it for the time being.