Absolutely! We had a SALT assessment recently (private, for tribunal - think it was CELF) and ds scored within 'normal' range in most areas. But when it came to the sections testing understanding of social situations, anticipating others' actions, etc he was around 18 months delayed.
The tests done by the NHS SALT (who saw him once for the statutory assessment) were nowhere near as in-depth as this, with no formal assessment of anything relating to social understanding etc. Consequently he was judged to be within normal range in expressive language, and he has no SALT provision other than 3 'advisory' reviews a year in his statement.
Anyway, sorry to hijack with a rant
Great achievement by your ds, esp considering his language delay (probably more relevant to this than the ASD??).
Just wanted to say 'Hurrah'! to you & your DS! (my DD has speech/lang delay, so I can imagine how excited I would be to have your results) - well done to you both! (*Cheers & flag-waves enthusiastically!*)