Cyyap3
Don't know where you are getting your info from but Airbus SO's mainly fly on the 330. To everywhere but perth and cairns in australia, bahrain, dubai, bali, saudi, karachi from bangkok, the 340 trips are only rome, moscow (soon), auckland and vancouver oh and south africa in their winter. Don't think there are many more 340 trips the SO's do. When you start as an SO on the airbus fleet you are only on the 340 but after about a year you get to fly the 330 also and then most of your trips are 330. Not every flight that has three or four cockpit crew has an SO on it.
Cathay do not fly to YPPF unless you count the cadets still training as cathay flying there. We fly to YPAD.