Many psychiatrists will include an ADD diagnosis if it explains what is going on. Usually this is added to documentation for education or work accommodations. ADD symptoms in AS don't usually respond to stimulants as well as ADD/ADHD.

I mentioned my suspicions to my psychiatrist. She considered it and did an ASD evaluation. Some doctors are open to suggestions, especially since a lot of people research their (suspected) condition(s) online.

You can mention you are concerned about ADHD, sensory processing disorder and AS. It indicates open mindedness. If you went to the appointment stating you have these conditions it may not work out.

Maybe you can make a list of your symptoms to help you describe how they impact your life.