Since SYD-OOL is now $63 (which should change back to $103 soon), I plan to I stock up several N-class tickets for future travel through to Sep 30th.

However, if I want to change dates after the sale is over, does anybody know if I have to pay difference of fares ($40) in addition to the change fee ($33), provided I'm only re-booking onto flights with "N" availability?

Since I'm only rebooking within the same booking class, I don't see how Qantas can legitimately charge me extra $40 fare difference. Any insights?

Thanks