Table A Max FDP 3 sector day: 12 hrs 30. Departs HKG 1330 back in HKG 0115. Thus if all runs on rails FDP 12 hrs 55. In flight relief of say 3 hrs provided to operating pair gives them an extension of 1 hr 30 min. Relief crew get no IFR and so burn out on third sector. CX are giving relief crew full credit hours for this third sector even though 'burnt out'. So I guess this means that the "is this PXing on the freighter" question does not raise its head??