20/40/60?
You are supposed to be pilots and good with numbers. 20/40/60 won't save them much money. It will probably cost them money. It's all demographics. Also think about the 5 year picture. How many expats will have retired? However, the ever increasing demographic of HKPA people will have seen their HKPA double. Think of all those new joiners to do those 2 x SO flights joining on $20k instead of $10k.
20/40/60... Nah... Can't see it sorry...