Might be compounded and packaged in a Cenex plant, but you can bet that it is done to Viscosity Oil's specifications and recipie. There are a limited number of compounding plants and most have excess capacity. When a company such as Viscosity needs product they will advertise for a bid for so many gallons of oil is cetain containers, but it is with THEIR FORMUlATION not the winning bid plant's. For example I have been to the Shell plant in Woodriver, Il a number of times and have seen numerous other brands of containers on the like. Gurantee that the formulation is not the Shell product, but rather the customer's spec.