Yes. Do you have proof otherwise? Explain how a thinner oil with a lower HTHS is anything other than a friction modifier to reduce drag and increase efficiency? I'm holding my breath because
kschachn is right you sadly do not understand the "winter weight" labeling and somehow think at ambient 70F there is some statistical difference in viscosity between a 0w30 and a 5w30. So I am fascinated to hear your research and physics documentation on what else 508/509 does besides increase fuel efficiency?
Price does not dictate anything other than what is being charged and what people are paying for. I can buy a part from FCPEuro made by the exact same company that makes the same part for the OEM, the only difference being the logo stamped on the part. One is more expensive, part is the same. There is certainly some additional R&D to recover from 508/509 but 508/509 is not made using Unobtanium and Unicorn Tears.
I mean, do I need to point out the irony? It's pretty obvious. You lecture about how the Europeans have been doing long drains and know what they are doing....then you state NO ONE should question the engineer......and then you state you do something different because you don't trust them.
Rrrriiiiggghhhhtttttt.
By the way......CLEARLY I know better than the VW/Audi engineers. That's why I am running 25+ psi of boost in my Golf R, it's why I replaced the brake rotors with slotted full floating 2-piece rotors, it's why I replaced my shift linkages with better parts. It's why my TTRS drinks E85 and is capable of 540HP+ on a pure blend of the stuff. It's why my Allroad now sits 2" lower and will be getting a boost to over 300HP soon. In reality the engineers did not design those cars to do that, so their recommendations for those puttering around town in "D" on the gear selector has no meaning to me. It would be like asking a butcher how to plant a garden.
Oh and before you lob your pretentious strawman at me I'll answer up front. No, I will not warranty any engine failures someone else has. What someone else does with their property is up to them and if they are making their sole decision on that important of a choice based off a post on an internet forum that's on them.
That doesn't mean we can't share information to consider and people aren't free to do their own research if they so choose. If you prefer to stick your fingers in your ears and yell LA LA LA LA and happy in your own assumptions and expectations it really isn't going to cause me any loss of sleep.
Me? I looked into the new spec, talked to HPL who actually MAKES oil, and only then sucked the ridiculous 0w20 factory fill out of my Allroad and put in some sweet HPL 5w30 for some protection while pushing 5000RPM+.
Oh....and I'm going to change the oil after 5000 miles too.
Of course if you read the manual the engineers printed you would see they list a whole mess of driving conditions that adjust the base recommended OCI and I am willing to bet you do more than one of them and ignore the engineers by going longer.