fwiw the blocked seats are always released closer to flight time (when varies by route but typically a day or 2 before). As for getting a cheaper fare on a route, the LCCs such as Tiger and Jetstar will always be cheaper than QF. Most of the cheap QF fares require advance purchase, I've had to pay AUD 800 for economy fare SYD-CBR on some days so it could be worse, QF really has the supply/demand equation down pat to maximize yield.