So mad and yet SO Proud!

I have been so mad at my son all weekend but at the same time I am bursting with pride. They take tests at school called WEST tests (for you older folks like me they are like our CTBS tests were) and they got the results back this week from last years tests. The results come in levels- Novice, Partial Mastery, Mastery, Above Mastery and Distinguished- and just to put the levels into prespective, my daughter who makes almost straight A's got 3 Mastery and 1 Above Mastery. So my son who makes C's in school and swears that he is doing his best, that he just can't concentrate for long periods of time - what does he get on a test that requires you to sit for hours and fill in dots? 3 Above Mastery and 1 Distinguished!!!! Excuse me? What did you say? I don't think so. Yes he is a friggin' smart butt. Hubby says I can't start pushing him or he will just back off completely. So what am I suppose to do? My friends suggest rewarding him, yes that is probably why he did good on the tests(they are taking the ones that got All Mastery and above on a trip) but should I have to reward him to get him to do good. Shouldn't that be a requirement? I am so frustrated but at the same time I am so proud. We knew that he had a brilliant mind, he just didn't seem capable of applying it. So how do I get him to apply it to his everyday work? I have no idea but I will find a way.