I have found another thread discussed the same issue.
http://giftedissues.davidsongifted.org/BB/ubbthreads.php/topics/82197/1.html . My son said he usually is the last one to turn in school work except math sheets. Friday his teacher wanted him to take some unfinished work home to finish which was the work from a month ago. When he went to afterschool science class (which he enjoyed), he also always the last one to finish building the projects. Except school work, he is not a slow poke like DD6. Besides he has faster reaction than me and DH while playing video games. I think the visual-motor coordination did play a role of poor writing performance but not the major reason. The things he is interested or not are more important for him. Mich, your DS's situation is the reason I am worry about. My son's small problem right now will get bigger when he enters MS. How do you handle this problem?
DS also has difficulty to answer open-ended question. He usually will say he is not sure or cannot decide. His world is like a digital world, only 0 and 1, any ambiguous problem will stuck him for a long time. His social skill is kind of lag behind than average kids. In social situation, he is seldom aware of the environment. Most of the time his mind is preoccupied his own world. Maybe that is why he got low Comprehension score. How much VCI will be affected by language expression ability? His reading ability is 4-5 years ahead of his age but he only got 86% on VCI.