I hear what you say, but keep in mind that Disney sometimes seems to try to discourage people from getting
DAS, to say it politely. They can push back. Be really clear in why your child (/your party) will benefit from waiting outside the lines. Use the experiences at the local theme park as an example. Why didn't he do well there, and how could DAS improve the experience at Disney.
And also, just in case, if Disney decides to deny you DAS, have a plan.
For example, know where the quiet places are when your child gets overstimulated, etc. What is the max your child can wait before getting worked up, if you know it's 30 minutes, do not get into a 60 minute line.