For Mazda North America USA, Canada and Puerto Rico all follow CAFE regulations. Mexico does not follow CAFE. The 5w-30 for Mexico in your OM is API SM rating, there is not a specific stated API rating but needs ILSAC seal for our area. I can only speculate on why Mexico is different. Oil availability, severe service, CAFE, exc. Around the world the 5w-30 shows up but the oil service interval is longer. Also Japan and North America (except Mexico) oil formulation is made by Idemitsu and the 0w-20 is loaded with dinuclear moly. That factory installed oil (0w-20) ships around the world but for Europe another Mazda oil made by Total (0w-20 and 5w-30) is used after the break in. If you buy a Mazda with a turbo the oil used is 5w-30 and does not have that high dinuclear moly.