Do you refine and blend your own motor oil? If so, shouldn't the gasoline/oil price ratio be comparable on domestically produced motor oil?
I don't know much about this sort of stuff.
Australian oil companies like Penrite and Nulon certainly do blend their own oils, many of which are unique to the Australian and New Zealand market.
We have oil and refineries in Australia, but I don't know where the above companies source their base oils.
I hear the price we pay for petrol (gas) is more a reflection of international market prices and less of production prices. We have a big tax on fuel in Australia, so our prices are very inflated with respect to North American prices.
I'm sure others know more about all this than I do.