The manufacturers of even the finest European formulations primarily consist of US companies (US & UK), including the renowned big four (Infineum, Lubrizol, etc.), and the corresponding American corporations behind them.
The American specifications, namely API and ILSAC, enjoy significant support from the US oil industry and petrochemical businesses. API, functioning as an industry lobbying organization, is structured in a manner similar to a small lobbying company, yet it serves as the creator of the best requirements-forming system. This is made possible by the strong industry presence behind API, including connections with national laboratories (ORNL, NREL, and others), dedicated topic-specific laboratories (SwRI), and, of course, all the companies involved. SAE and even JSAE contribute to these efforts. The involvement of Japanese companies is particularly noteworthy, as they were early adopters of soluble MoDTC since the mid-1980s, while British companies have been using soluble tungsten since the late 1960s and now explore the utilization of titanium. This cooperative relationship between British and American companies in the industry is quite strong. The API and ILSAC requirements exhibit a verified scientific level of quality and scientific nature. Every aspect is carefully measured to strike a satisfactory balance since the formulation of oil necessitates compromises.
The European Union, in general, although boasting a strong automotive industry in Germany and to a slightly lesser extent, France, lacks sufficient expertise in the field of petrochemistry. Even the largest European company, Total, relies entirely on compositions derived from American and Asian experience when formulating oils. Not to mention the development of the additive packages themselves, where the EU has limited experience. Complicating matters further is the fact that the EU is not a single country, although control in professional matters in this domain is delegated to more experienced nations, such as Germany. Hence, organizations like ATIEL or ATC serve as superficially bodies only (ACEA). The EU does not possess the same laboratory and scientific infrastructure as the United States, and I dare say that their PCMO requirements are often lacking justification. However, it is worth noting that their requirements are, of course, coordinated with key Global additive manufacturers. For instance, Infineum is willing to assist and fulfill the EU's requirements, although the effectiveness of ACEA approach is subject to scrutiny.
It is widely believed that everything European of high quality embodies excellent taste and style, characterized by stringent requirements. However, in the case of oils, it appears to be different. The United States holds the best scientific foundation in subjects such as rheology and petrochemistry. I find European PCMO requirements often tend to be excessive, considering that oil formulation is inherently a process of making compromises, not exorbitances.