mmm I for one would be surprised to see them use the A330 to Perth when it's well within A320 range from KUL - would be a good overnight aircraft utilisation. Why run when you can walk?
Why when you consider Perth is a busy internatinoal airport for the size comparisement.
4 x PER - SIN = SQ
2 x PER - SIN = TT
You may find that the A320 ops may be payload restricted