my experience with 1st year socs is that each class can be very different.
for example: 2 hours of lecture: 2 classes @ one hour each plus 1 hour of tutorial
3 hours of lecture: 3 classes @ one hour each and no tutorial
3 hours of lecture: one REALLY LONG 3 hour class but you only show up once a week and no tutorial
and there have been classes where there is only one core and the tutorial is assigned so you have no choice as well as ones where i can choose..
it takes a bit of getting used to.