We had ds14 tested at age 6 at the request of the school. He was not settling down well into the classroom and was behind in reading. We had a reputable psychologist test him all in 1 day with all the subtests of the WISC-4. He also was given some achievement testing. He did ok but did not test gifted at that time. I think that a full day of testing for my 6 year old was too much.
He sounds similar to my son... tested at 7 (at the request of the school), and the psychologist said that he should be retested in 2 years because the current results "do not accurately reflect his potential." He tested as having Expressive/Receptive language disorder and ADHD combined type, with a "solidly average" cognition level. She told us to take the results with a grain of salt; she could only get :45 mins of compliance out of him for each 2 hour session, etc etc, so the results, although they represented his level of functioning at testing time, were not accurate overall. Meanwhile a rep at SENG who I contacted said that it's not a good idea to test kids before the age of 8 (because prefrontal cortex developmental delays can interfere with testing performance).
Sigh. We had one time coverage, and now it's been used, on a test with "inaccurate results."
Oh well... life goes on...
They support your case that he was too tired to test at his actual level.