The other problem we have with the EU rating system as it is, is that people will treat it as gospel when it happens to reinforce the beliefs they hold about a certain product, but the moment things don't quite go their way it will be declared inaccurate or rigged!
With different products being tested by different labs, nobody can be sure the tests are 100% accurate across the board. Of course, each lab will be working off the same testing methodology laid down by the EU, but there's no way of knowing if they're all implementing it in exactly the same manner. Now, if all appliances (not just vacuums) were tested by ONE internationally recognised independent test institute, you would eliminate that concern from the get-go. The issue here is, every other testing organisation would scream there was a monopoly, and manufacturers would complain that it wasn't as cost effective as nominating a lab of their own choosing.