Actually, all you need to do is look at the way everything starts failing on most Asian/American cars the moment IIHS changes their testing procedures. Impact in a slightly different way, and you bypass the system set up primarily to ace a specific test. European cars tend to fare better- MB needed a software change to most of their cars to get the airbag to deploy in the small-offset tests, but otherwise passed, while all Volvos passed, and the XC90 was best performer period- despite it being a 10 year old design at the time.
Safety designed around a specific test is an inherently flawed concept, because accidents dont happen in specific laboratory environments. Eschews comes to mind- it wasnt designed to deal with snakeheads, bridge pillars, or bridge collapses. I doubt if American equipment would have done much better, though.