Help with assessment outcome

Hi,

Hope it's ok to post this here but I'm really not sure where to go. My 18yo son has been through the assessment process and the report has come back to say he hasn't received a diagnosis as he didn't meet the criteria. I've had a follow up call as I didn't really agree with some of the observations in his report from his in person assessment, and actually following the assessment he was very shut down and exhausted for a few days, as he'd tried to hard to mask his usual behaviours. During the call it felt like the response was 'as he can learn to correct his behaviour, this doesn't fit with an autism diagnosis', but isn't this just what masking is?

I appreciate I'm probably overly emotional following the call this morning, but am just looking for advice really and whether anyone has been in a similar situation? Is there a 'next steps' or do i just let it go?

Just to add I could be being especially sensitive as I myself have been late diagnosed and in all honesty I just don't want that for him.

Thanks in advance!