its probably for MCE (Multiple Criteria Entry) at the Engineering Faculty... a lot of univerisities have those types of things for engineering...
at UNSW, they've still got second round interviews for people whos UAI/HSC didnt come out as planned, where they assess your preferences based on UAI + any modifications as would be indiciated by subjects and marks and such... although MCE only applies for UAIs between 75 and 85...