On the QF8 service DFW-BNE, you can't rely on the seat available figures shown on the staff travel website as it doesn't take into account that seats are blocked off to keep the Zero Fuel Weight down so that the range is sufficient to reach Brisbane - the aircraft always departs with full fuel tanks.
Personally, I'll never risk staff travel ex DFW (it's fine going SYD-DFW) and will always return to Oz via LAX.