This new evaluator should assess on his own for ADHD. He should NOT rely on a pediatrician's diagnosis. There are many childhood disorders whose symptoms mimic ADHD, and it's important to figure out if you're looking at true ADHD or something else entirely.
For a three-hour testing session, there are many different activities for the child to do within that timeframe, plus there is generally a break with a snack halfway through. Furthermore, these evaluators are adept at dealing with children with various disorders, and know how to get them to attend to the task at hand. If the child can't attend, that is information in and of itself.
