I posted this on a separate thread, but thought it deserved a new post of it's own: What is the basic difference between the OCI's recommended in N.A. and Australia? Does Aus. have better oils? Better oil standards? Better/different oil grades? Better engines? Better quality gas? If so, what are the standards? Do Aus. oils not relegate to API standards? Are their grades on a different scale? Are OCI's climatically related? It's known that in Eur. and Aus. a qt. of oil doesn't cost .99 cents (not even close), however if the average or even best conventional oil could go 15k km, then why are we being told to change it at 5k km?