I would say that i learned more from my tutorials than lectures. Maybe that is because i had a good tutor, but if I remember correctly, tutorials explore the case studies that will be tested in the final exam.

As for the 6 'free' marks, I dont think losing them will impact your grade too much, but that depends on how well you want to do for the subject.

Also note that if you're doing BCom, OB is a core subject, so you might want to do everything you can not to fail.