My son's higher score was also applied problems, above the computational tests, consistent with the lack of workbooks in our house. So far he's skipped two years of math (1st and 3rd), currently in a compacting class (4/5) with a gifted intervention specialist, and hopefully will do one more year of compaction at the middle school level after next year.
We're finding that when learning math in a classroom setting, acceleration is as much an issue of being able to deal with the format of showing work, verbalizing reasoning, checking work, etc, is the primary barrier to moving through the curriculum faster. DS is so far lucky to have been extremely well matched with teachers who have stretched his thinking nevertheless.
