Mobil also confirmed for me that there has not been a formulation change to Mobil 1 Advanced Fuel Economy 0w30 and that the WSS-M2C953-A1 spec will be on the new bottles in the future.
I know this is an old one, but I could not find a good answer here or elsewhere. I just got off the phone with ford. They told me the wss-m2c946-a is the american part # and the mss-m2c946-b1 is the canadian. They told me it was the same thing.
Have a 2019 F150 Limited with the high output 3.5 ecoboost. It calls for the Ford ---B1 spec. Been using Mobil 1 Extended Performance, 5w30 since draining the factory fill as it shows on the container that it meets Fords "B1" spec. As an aside, so does Castrol Magnatec 5w30 which seems to be a popular oil for these engines.