i have not yet thoroughly read the hand book yet, but let's say for eg, the requirement for the adv stream of sci is that u completed at least 50% of ur cp in adv level...
now, let's say that u are enrolled in b sci and forgot to tell them u want to be in adv stream (like me), at the end of ur 3 years degree, u successfuly completed say 75% of ur science subjects in adv level...the 486 of usyd runs a check of all candidates that will graduate, and then *light flashes~~~ they realise that u are enrolled in b sci, and are eligible for the adv stream, they upgrade ur degree to adv sci with u extra cost...
would you like fries with that???