I understand that many oil blends out there meet certain specifications, but does this mean that they all have the exact same predefined CoF/Friction Modification (set at some value) and frictional characteristics??
Put another way, would it be more intelligent to expect them to all behave exactly the same in every physical way, because they meet identical specs-- or to expect that they would all have different and varying characteristics as diverse as their chemistries, despite all overlapping in pointed specifications?