How to find and understand the coverage information for autism evaluation for adults in my plan document (UHC/UBH)?

I have UHC/UBH/Optum and I’m having trouble finding and understanding the coverage information in my plan document. Under the “Mental Health Care and Substance-Related and Addictive Disorders Services” section it says “This section describes only the behavioral component of treatment for Autism Spectrum Disorder. Medical treatment of Autism Spectrum Disorder including the screening of a child for Autism Spectrum Disorder is a Covered Health Care Service for which Benefits are available under the applicable medical Covered Health Care Services categories in this Certificate.“

It says the evaluation of a child for ASD falls under medical treatment, but I’m unclear if that means an evaluation for an adult is also considered medical treatment and how much is covered. I looked through the Covered Health Services section on my plan but was having trouble understanding which category it falls under. I’m ultimately trying to figure out how much is covered for adults (if anything), what the limits are, if it’s only covered if medically necessary (and if so, what I can do to prove if its medically necessary). Need some guidance on where to search for this within the document.