As to GAI...with the processing speed I'd imagine GAI is a better indicator of overall academic success and intellectual ability. Ask your test if she/he will calculate GAI as well for you. Lower processing speed, from my understanding, is not unusual for young highly and profoundly gifted children.
My understanding is that VCI, and in particular working memory and processing indexes are important for success in a typical school. I certainly see this at home with my DS; he is intelligent but his deficits in executive function makes school and homework a challenge at times. Fortunately he is doing well now, but I worry about this impact as he gets older.
What really matters is understanding the root cause of the lower scores in working memory or processing speed, and understanding what's at the root of executive function challenges. There are many reasons that you may see these issues, and many of those reasons can be remediated/accommodated. Our dysgraphic ds has similar spread in coding vs other scores as the OP, and when he was in elementary school was extremely challenged with organizational skills. He receives accommodations for the challenge that impacts his coding subtest score (dysgraphia - he keyboards in all classes plus has accommodations for testing and other dysgraphic-typical accommodations), and we were able to remediate the organizational challenges by working with him intensively on those skills during 6th grade. Today he's doing very well in school, and isn't being held back at all (grade level/acceleration etc) by the disabilities that impact his coding score and executive function.
polarbear
eta - I'd add that in some ways, I feel like it was easier for ds to make progress in remediating and using accommodations as he got older, because he was able to understand how his challenges impact him and be an active part of coming up with his own solutions.
