You are very lucky. I have tried some HKG-BKK booking, flexible with dates, but no luck. Neither to SIN.
TPE-BKK was wide open.
My impression after a lot of research is that CX opens availability for some weeks (not many) but not for most. And it does not change over time.
I was looking at flights with light loads (and tons of availability for married segments or AM) over a two-week periods and nothing ever opened up.