Haven't heard similar stories from Europe, but in the USA
auto manufacturers are forced to meet corporate average fuel
economy (CAFE) standards of the federal gov't., and one
approach has been to attack internal engine friction,
resulting in (among other things) recommending 5W-30 motor
oil.  Now it appears this is taken further by the switch to
"SJ" rated oils, wherein (again among other things) zinc
additives are reduced.

This has created much talk on motorcycle lists regarding
lost protection when engines and transmissions share the
same oil and, more to the point here, when engines are air
cooled.  The feeling is overall protection may be lost for
air cooled engines experiencing high temperatures.  While
the reformulation may be more relevant to the lighter
viscosity versions of a particular oil, there remain
questions.  Anyone heard anything else or know of links to
good information as regards SJ oil in air cooled VWs?