They test you at the beginning of training and the again at the end to see 1) whether you came prepared in the first place and 2) if not, that you took responsibility to learn what you missed the first time around when you take the test at the end of the course.

I would not freak out if you screw up the first time through -- many people in my class did. However, by the end of systems you need to know every limitation and be able to recite every QRC checklist from memory or you're going to raise red flags during sims.