CELF 4 Assessment

[Kitty1850]

Advice please. Sorry this is so long. I didn't really know where to post this so sorry if this is in the wrong place.
My son is in year 4. He is real book worm and and loves to read above all else but hates writing and sometimes outright refuses. He has driven his teachers nuts since year 2 with this "problem". He is very happy at school but they sometimes have problems with his behaviour and he really knows how to push the teacher's buttons - brilliant and cooperative one minute - disruptive and unreasonable the next. His teacher describes him as "um, quirky". They recently decided to give him a CELF 4 assessment. Don't really know why they started here but I think they were thinking of the possibility of High Functioning Autism. I really don't think that is an issue as he is very empathetic and touchy feely.

These were his scores:
Core language Score 133 99th percentile
Expressive Language Index 136 99th percentile
Receptive Language Index 123 94th percentile
Language Content Index 129 97th percentile
Language Structure Index 132 98th percentile
Working Memory Indes 97 42nd percentile

The school's initial attitude seems to be "that's fine then, there is no problem". No, no problem but still way outside the "normal" range. If the results were this extreme in the other directions all kinds of alarms would go off, wouldn't they? I'm also concerned about the discrepancy between the other results and the working memory one. What should I be asking for next from the school. Or should I just leave well alone as he is a happy, well adjusted little boy generally.