Yes for twins/triplets, they can choose to either ballot individually (means each child gets 2 slips) or collectively (means 2 slips for each set of twins/triplets).
For the former, only the child that gets picked will get a place and the twin that doesn't get picked will have to go to another school. For the latter, the whole set of twins/triplets will go through. So you see, it is a calculated risk on the part of the parents, they get fewer slips but if they win, they really win big!
If these twins/triplets were to be picked last then the school will have to create more places for them but since they weren't, they took up 7 out of the seats alloted for P2C. Like in St Nick's Girls at P2B, the twins were picked last and the school had to take an extra seat from P2C to give it to them at P2B.
