When I recently took the ASA 101 course (3 Sundays, IIRC), I had very limited experience with sailing. I could not repeatedly perform the MOB drill to perfection, and the instructor would not pass me until I could. He brought me in for 4 additional hours of practice on his own time. We worked until I could do it SPOT ON.
I feel that with any certification course, you get out what you put in. If your just looking for a stamp, do the challenge. If your looking to perfect a technique that may one day save someone....Just my 2 $ from a nube. Best of luck either way.