Same here (taking 2 domestic rts a week at the moment) - Seems to depend on which port, funnily enough. Out of Sydney on a 767 its almost always 23 or 24 (have "forward" profile - not aisle or window as dont care about that on 1.5hr flight, just "forward"). Out of Melbourne its sometimes row 30 odd. I asked about this and got quite a lot of info. There were 2 reasons given: one was that they are increasingly using different 767 variants (ex international 767-338 rather than the -336 BA leasers typically used on DOMs, I guess that 767 is now used less international post A333s) and the editing (seating) system is not set up for these types which dont have full rows until 25 or 26, but the system still allocates the seats that aren't there in the front rows in order of status, and then those guys have to be manually placed later as exceptions - when fewer seats are left, so you will be behind somebody with less status. Also they said that "editing" the flight is done by the actual port of departure the day prior. Some ports (looks like SYD, but not MEL) seem to be better at recognising status than others.

Quick Check also matters (especially on 737) as the seats left vacant by editing (apparently the editing process tries to leave spare middle seats empty up front) still become "white" and available on quickcheck so some once a year flyer might grab them...

And alphabetical order of surname still rules within status of course, so WP ms Aardvark with forward aisle pref will be in front of WP mr Zebra with forward aisle pref.

At least they are mostly short flights so no real worries however you end up seated.....