There is a paper somewhere stating that it is normal for gifted students to have a big spread between their processing speed score and other scores. I think the average in that study for gifted students for processing speed was around the 110 range. It doesn't necessarily indicate a disability. DD was more like 94 for processing speed which was a 50-60 point gap from her GAI, and it was very evident in her daily work.
For writing there are written expression/fluency probes that you could give her at home, with published norms, just to see somewhat informally if she is operating at grade level on your own. Basically you give her a random starter phrase or sentence, she gets 1 min. to think and 3 minutues to write and you add up the words she wrote. Then there are norms stating how students in each grade perform. This is all online. Search for "CBM written expression (or fluency) probes and norms." DD was always about 2 years behind whenever I did this. I brought her writing probes to the school for a 504 meeting and basically just got blank stares. The districts that we have dealt with don't seem to understand how to evaluate progress with written expression (at ALL).
