I know exactly what you mean. I finished in 2 hours. and then went over my whole test adding things fixing it up. then i spent a good half hour on my two diagrams cause i had nothing better to do. You could feel the rest of the state gaining marks while you couldn't get anymore. it sucked.
The rest of the state only adds up to around 1500 students, and Engineering is a hard subject to get counted if you do 12 units. Anyway, I'm glad its all over, this subject also won't count for me...unless it happens to state rank, which it won't.