Some of the AOC's should be standardised in the EU and should utilise the JAROPS discipline. As with everthing though I believe there are only 33 signatories to it in the EU and the USA does its own thing on both counts. Many countrys are also limited to their level of compliance and conformance because of financial constraints. I believe that long term the idea is to have a regulatory standard that would be applied worldwide, but its likely sucess might be compared to organisations such as NATO and the UN ? In other words many countrys AOC's are directed by their CAA and conform only if it suits them.