I know, and I used 0W40 for years in my 04 C240.
I had to buy it at auto parts stores and pay through the nose.
If and when I could find it.
Previous to that, Esso (Imperial Oil) introduced XD-3 0W40
with a KV100 of 15.7.
We lost our Esso branded products when Imperial bought
Exxon/Mobil. Mobil brands are now available at
bulk Esso distributors.
For the longest time, all we could get was the reasonably
priced XD-3 and the over priced M1 0w40.
A few years later Pet-Can rolled a very cost effective 0W40 Duron,
at half the price I was paying for M1 0W40.
I bought a 20L pail and tried it out in the Benz,
oci 25% past the OLM at around 21,000Km.
The UOA looked good, except for the 5% fuel in the oil.
Esso, at this point had not re-branded the XD-3 to a Mobil label
that I knew of, so Duron became my 0W40 go to oil.
I learned that the introduction of 0W40 was not all
roses for other brands, many experiencing major thinning
out of grade.
Because of that history, when a new 0w40 hits the
market from North America, the HTHS is 10w30ish,
the KV100 at 13.3 and there is no license or
certifications.... I'll pass thank you.