Has anyone else noticed that Castrol has issued new MSDSs for their German produced 0W-30 and 0W-40 products? The latest documents indicate >=25%-=50%-<=75% PAO.
Valvoline Synpower contends they provide better film than Mobil 1. Both I believe use SOME PAO. PAO might flow better but grp 3 and 5 might have a better film upon startup. Castrol Magnatec is said to be on 3 and 5 group and that might make me believe its for oil film thickness and startup. If its got too much PAO it might pump quicker, but a film of lubrication already present is more important. I wouldn't lose sleep over this. Let your butt dyno and UOA tell otherwise.
Be careful that an MSDS isn't a recipe. A change in pour point could be indicative, but we've also had weird Castrol sheets for years, and they may finally be sorting things out and correcting them. The pour point shown might have been for the product at its introduction, for all we know.