I still have some RGT from the AZ closeout and I thought the same thing that you wrote but now I wonder. Yesterday I came across Lake Speed Jr. YT video called ‘The Hidden history of Mobil 1’ where he compares different varieties of Mobil 1. I was surprised that Mobil 1 Truck and SUV was stouter (higher oxidation resistance) than regular Mobil 1 in the same viscosity grade). This got me wondering if SOPUS did the same with RGT since it was also aimed at trucks and SUVs. What are your thoughts on this possibility?It was basically QuakerState FS in a red jug.