The appearance would be that the ULH economics and fuel burn of the B789 will always beat the fuel burn /economics of ULH A380, right up to the point where you run out of slots with curfew constrained airports and then you are screwed.The other thing people haven't considered is the negative perception around the 9 abreast B787 product that is becoming more and more public, I suspect that with these lengths of flights that the seating will actually depress yields and pax demand. People may try this in Y once and will then say never again, sure the PE and J yield may keep them alive but all it would take is for BHP and Rio to have a bad run and the J yields would vanish as well.Put it this way - who ever got off a 9 abreast JQ B787 flight in Y to-from Australia to Japan and thought - you know what ? I'd really like to do that for another 10 hours please, and pay through the nose for a non-stop rather than a huge choice of 1 stop competitor options with a superior Y product. Its a stretch too far by the QF accountants - and just like the 2-3-2 J class on the A330s they will be ripping out/reconfiguring their B787 fleet in the future if they keep them on ULH routes.QF PR can spin all they want but once fuel prices go, up or another competitor starts B787 or A350 or B777-X services that compete with a lower cost base, then this LHR-PER-MEL route will be toast.