Well, your daughter has spoiled you. LOL! We have a wonderful daughter, as well.
Your son's daily work scores look exactly like my son's! We have asked him, and asked him why he doens't finish things and he doesn't know. So we take away his games until his scores come back up. We have arranged for him to stay after school to make up class work. It really works. I mean, he lives for his games.
I do not think he will value school work any time in the near future (or even until the sun super-novas) but at least while he's under our roof, he won't flunk out.