Thanks for the responses.

The testing was done with a private psychologist, not through the school. He thought that the WISC IV + Conner's scale (parents and teacher) + reading comprehension + writing test would be enough to determine any learning difficulties. Based on the results, he said that DS is verbally gifted but has a NVLD (but not ADHD, I think based on the Conners score?). The NVLD was based on the big difference between the VCI and PRI and also his relatively poor result on the writing test (which I think was not really representative). Would a neuropsychologist do a different battery of tests than a psychologist specializing in psycho-educational assessments?

I may not do any further testing right now, as DS10 feels that even the tests that we have done so far are a "waste of time". He sees himself as a "normal, average kid". And maybe in a way he is right -- perhaps his strengths and weaknesses average out so that he functions more or less like an "average" child in the class (now that I have taken him out of the unstructured Montessori program, which in retrospect was probably not a good choice for him).

I'd like to know about possible future testing though, in case his organizational issues start causing him more trouble later on.