I'm confused by this. All the cheap tickets that I have ever bought from DJ, JQ or QF were highly restricted (more so than in the US); flexible fares were available, typically at double the cost. The Aussie airpass is fully flexible (you can even change destination). The experience you describe is the opposite -- which confuses me. I found the Airpass was no cheaper but a lot more convenient and avoids the need to throw away tickets that can't be used (which happens on the cheapest fares in Oz if your plans change).