It is my understanding that you can request testing every two years. I'd write a letter and send it to the screening committee and special ed chair at your school requesting new testing for updated developmental markers and better placement and accommodation strategies. Putting it in writing sets the clock ticking, and they'll likely drag their feet but will have to legally address your request.
Another option is to make an appointment with a local psychologist who deals with adolescent ADHD. Almost all insurances will pay for the initial screening, and during that visit let the psychologist know you'd like updated testing for the same reasons as well as better treatment options for his ADHD. They can make a request and see whether the insurance will approve the testing. If so, it might be a better route, because the tester will be independent.
Good luck! (and thanks for all your advice on my own kiddo back when I was asking!)
