Basically you get two offers based on what score you met from your list of preferences.
So first round offers, you may have missed out on your first, second and third preference but been accepted for your fourth. With that you would accept your fourth preference.
But when you get your second preference you may have got your second offer, which you can then accept and call the university for your fourth offer and turn it down (even though you previously accepted it).
The second bit I'm not so sure about as I'm under both SEAS and SALT (La Trobe). But from what I understand an ATAR of say 70+ for a course requiring 70+ is clearly in, but left over space in the course is given to those that are say just under, (so all the 69.95, 69.90, ...) and SEAS.
Probably best to get someone to clear this up though mate, thats my understanding of it.
