You could also say that when you've got a quest you need to kill monsters acomplish your quest so that in one quest the exp should be the summ of the monster you killed + the bonus for completing the test. <img src="/ubbthreads/images/graemlins/think.gif" alt="" />
Blowing up the orc train:
To complete this quest you need to kill a lot of orc. So you can say that the exp points from killing those orcs is part of the quest. <img src="/ubbthreads/images/graemlins/think.gif" alt="" />