I notice that there are some changes to the fuel surcharge charged by CX to oneway flights arriving at HKG (at least for ex-JPN). In the past, the fuel surcharge for each segment, no matter which direction, is exactly the same as the one limited by CAD. However, since Nov, the fuel surcharge for roundtrip ex-HKG and oneway ex-HKG is still the same as CAD limit (roundtrip = oneway limit x 2), while ex-JPN is charging a much higher figure.

E.g.
OW HKG - NRT = HKD172
RT HKG - NRT = HKD344
OW NRT - HKG = JPY4500 = HKD300
RT NRT - HKG = JPY 9000 = HKD 600

Any one has any idea how actually is the fuel surcharge being regulated / calculated.
Thanks.