You only pay the taxes if you book through aeroplan- not m and m. I am not sure what the logic is on this- but it is a good deal for you! BTW I just booked a Star award bkk-syd-sin-bkk with Singapore and Thai- and was told I didn't have to pay the taxes as it was a Star award. As usual, a Phd in engineering may help in understanding the complexity of award and fee calculations...