ADOS shouldn't be the deciding factor, assessment for ASD should be based on a multi-disciplinary approach using at least SALT and OT, with information from school and Ed Psych if involved, and maybe other professionals. ADOS should also takes more than half an hour. I think I'd go and discuss with GP and request a second opinion on the basis that the first assessment was not carried out properly. Good luck.
My daughter who is 9 has been diagnose with sensory processing and dyslexia, she can't handle change and has meltdown, all the research I have done seems to link to aspergers. She saw a pedi who was 99% sure of aspergers and was sent for a ADOS test. It lasted half an hour and I was told she is not on the asd and sent home with no further follow up. My child Is now refusing to go to school, has mouth ulcers, because she is good at school (sits quietly and not makes a fuss) I'm not getting the help I need.