I looked at the CAFE requirements on their site and it requires car makers to *clearly* state in all customer documentation (owner's manuals, etc) that the oil used to certify the car must be the one recommended. So the car makers are caught between the law and a hard place in terms of recommending oil. Mobil is probably caught in the middle in the sense that they can't recommend an oil that is not recommended by the car makers that is not stipulated by CAFE law.