Hey Dad,
When I first started vacationing in France, back around 1979, I got the "brainstorm idea" that I would buy a case of Motul 2100 which at the time was the better Motorcycle oil sold here in the USA. I discovered two things.
1. What was being sold in the USA as their Motorcycle oil, was just a regular car oil in France. (Did not even know at that time that Motul was also a car oil as it was not sold in the US at that time.
2. The cost of oil over there, no matter if it was Motul or Mobil, or Total, or Elf, or AGIP was out of this world. Whereas a regular oil in the US at that time cost about $1.00 a qt, and a very good oil was no more than $2.00 a qt, and Mobil-1 was about $3.50 a qt. In Europe, the everyday (cheap) oils were more like $7.00 a liter and Motul 2100 was something like $10.00 a liter and Mobil-1 was more like $15.00 a liter.
Needless to say, I nixed the idea of buying over there and bringing it back. I had a friend living in Dijon and one day, I asked him how much did it cost him for an oil change on him BMW 316. (Now remember this was 1989 when an oil change in the US was around $12 to $15). He said it cost him over (the equivilant of) $110.00. I could not believe it. Today, because prices are higher, (not to mention the Dollar/Euro ratio is in the toilet), I know it costs even more, so thats why they go the full 30,000km (18,750miles) between oil changes.