I myself wonder at this, because Volvo says the oils must meet ACEA A5/B5... but most oils that meet this spec are 5w-30, not 0w-20.
The Volvo spec oils in 0w-20 I have seen meet ACEA A1/B1 and C5.
That's right, A5/B5 was the interim requirement specific for 5W-30 oils and it isn't in spec for 0W-20. They are exclusive of each other. The 0W-20 oil's spec is RBS0-2AE. This is how the manual in the US read; in the context of 5W-30 it must be A5/B5 when they were recommending a more conventional weight of oil in the US as an exception to their global standard. Note, ROW was 0W-20 exclusively.
See below, Initially in the US the manual was written specifying an A5/B5 based on 5W-30 as providing "good fuel economy and engine protection" under "normal use". And, it was always clear that for the best protection you should seek out VCC RBS0-2AE 0W-20 especially for "extreme engine operation".
Clearly after a few years of sampling 5W-30, it's proved not to be sufficient, there have been documented engine failures due to inadequate flow around the pistons (examples in this forum from 5W-30), and they've snapped the US over to the ROW 0W-20 using RBS0-2AE.
Case in point.. Castrol Edge Pro V 0w-20 is not an A5/B5 oil... it is a C5 oil.
This new insert makes it a clearer distinction that A5/B5 is for 5W-30 and exclusive of RBS0-2AE 0W-20. It also more clearly states, that RBS0-2AE 0W-20 is the preferred oil in 4-cyl VEA. And a proper warning indicating NOT to use it in 5 or 6cyl engines which weren't designed for use with that viscosity.
The VEA 4Cyl engines were designed with different and more precise tolerances for which 0W-20 is required as has been shown by other forum posts where piston rings and piston replacements demonstrated how 5W-30 tended to clog the rings. Upon engine rebuilds or replacements Volvo explicitly states use of anything other than RBS0-2AE 0W-20 voids any warranty that was conferred to the repair or new engine.
The move to 0W-20 is intentional for new fuel efficiency standards and in many cases, like in Volvo's new SPA cars, by design of the engine to necessitate 0W-20. A5/B5 5W-30 ultimately didn't meet the viscosity and wear requirements to adequately service VEP engines. Volvo's very proactive campaign direct to owners and through its dealer network makes it clear that 0W-20 is the engine oil that best works in these engines.
There are a few here who have either modified 😜 their 4cyl with parts from the P2 XC90 parts bin (2014 and older) that were designed for use with 5W-30 or synthetic 0W-40 for extreme use (what we use in our 2010), or know better 🧐 than engineers who designed the engines to work with specific weights. There have been a few posts mentioning consequences of using 5W-30 which have led to clogged piston rings and other issues which likely contributed to Volvo pivoting to their design standard to also apply in the US for the new 4 cylinder engines in SPA and CMA cars.