Great trick, isn't it johnyip.

Dave Noble brought this to my attention (as well as others I know like IainF, Alan in CBR and Craigo to name a few) over the past 12 months with his investigation of similar comparison fares. He sat me down and proved for my recent USA trip, that I would save ~$200 (and I did) as well as pricing some of my more common QF dometic trips - all of those in K class or above were worthwhile booking using AA Res in UK or USA, or the website (using the CC trick). I've saved around $1,000 this year from using this system.

One disadvantage (actually, more a point of initial confusion) is that my company reimburses my travel costs, so when I was giving my initial monthly expenses report, my CFO thought I had misrepresented the costs and forgot to add the GST (which there was for all my other expenses). When I showed them how I was doing it, my CFO and Chairman congratulated me for saving the GST impost. However, that concern is not going to worry you just yet, johnyip.

Having to ring AA to make any changes prior to taking the first sector can be a problem (but AA SYD are useful there) - once you're on your trip, changes can be made using AA or QF. That shouldn't stop anybody though