Originally Posted by Mad_Hatter
Maybe he's suggesting that the performance spec's of the oil have changed (for the better) over time
Yes, that is what I'm trying to say.
I believe ACEA was introduced in 1996 with input from all the major European manufacturers. As a central standard they could all use. It's still the base for all the modern Euro OEM standards, with a few individual tests thrown on top. You can't be MB or BMW without also being ACEA first.
The ACEA sequences includes things like sludge tests, deposit tests, cam wear tests, cylinder wear tests, valve train scuffing wear tests, etc.
(ACEA 2016 Sequences PDF)
The big thing is that these sequences have been constantly updated as engines have developed, and the test requirements have been strengthened, requiring a better developed and formulated oil to pass the tougher requirements of the more modern sequences. The sequences were updated in 1998, 1999, 2002, 2004, 2007, 2008, 2010, 2012, 2016 and 2018.
Given the OP has a 1998 Mercedes, but is looking at a modern API SN and ACEA A3/B3 oil, there has been a lot of updates to ACEA since MB printed that owners manual 22 years ago. That MB 229.1 would have been based on the 1998/1999 ACEA sequences.