(from a lubrizol article)

Creating Performance Packages

For passenger car motor oils, components are not sold individually.
Lubrizol formulates them into performance packages to meet various
market needs. For instance, in North America virtually all passenger
cars have gasoline engines. In Europe, over 40% of passenger cars have
diesel engines.

In North America, passenger car motor oils are engineered to meet the
recommended OEM oil drain intervals of between 3,000 and 7,500 miles
depending upon the type of driving-severe or normal. In Europe, oils
are engineered for longer drain intervals, often exceeding 20,000 miles.
The components needed to meet these needs are usually quite similar, but
the way we formulate them into a performance package can be quite
different.

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Why the difference?
US consumer resistance to longer oil changes. However API SL [for instance]
is API SL wherever you are and is formulated to meet the same standard and
is a staple for up to 12,000 mile oil change intervals in Europe with no
adverse consequences. The package supplied by Lubrizol and others is
different though but mainly because of the different crude oil blends and
base stock quality which varies from region to region. The end result is
however a consumer oil which meets the relevant standard wherever you are.
Oils meant for 20,000 to 30,000 miles are however formulated to much higher
standards than presently mandated by the API and are usually specified by
the engine or car manufacturer. Examples are mb229.3 and ultra long drain
mb229.5 multifleet [petrol and diesel] oils for light engines and 228.3
super high performance diesel and 228.5 UltraHPD for heavy duty diesels. The
International European standard ACEA also set higher standards which
generally reflect the mb ones. GM has its own long drain standard as has VAG
and BMW. All the additive packages for these oils are supplied by
specialists to refiners or blenders to achieve the finished consumer
product.

Huw