Adult autistic diagnosis of 4

My son was diagnosed in 2014 at age 25 with autism, on the copy of the diagnosis it says he is a level 4 ,can anyone tell me what 4 means ,is there a scale as to how badly a person is affected, thanks in advance 

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  • Aren't there only 3 levels of autism? Even those aren't very useful. They're all about functioning and whatnot. If your son didn't get diagnosed until 25, then I guess he's probably at the higher functioning end. Sorry I can't give more info but I haven't heard of level 4. Perhaps you should ask the person who diagnosed him.