Weaker add pack = shorter possible OCI.
It's blended to be a very low oxidation oil I think so that it can do long OCI's
In Europe it (VW504.00 VW507.00) goes up to 20k intervals in VW petrol engines and up to 30k in VW diesel engines, you just need a new turbo at 150k
In all honesty i have only heard of one person running the longlife service schedule on a Passat.
Only fleet managers are interested in the kind of cost savings they represent.
Also VW appear to quote 18k or 2yrs.
And they add caveats like covering more than 25 miles a day and use on longer journeys etc.
Fixed interval servicing every year is advised for those doing less than 10k a year.
The OCI on my Pathfinder is 18k (and i think 24mths) for example.
It had 90k on it at just over 3 yrs and had all services done by mileage. The actual vehicle drove round the M25 London orbital motorway twice a day from Crawley to Bluewater Shopping Centre and back. So was used in ideal conditions.
In the workshop manual it clearly states not tk run the oil for 18k in a vehicle used in severe service, which includes stop start urban running.
The only reason there are issues with long oci is when they are used wrongly.
Like leaving the oil in situ for 24months when the car is only ever used to do the school run.