I'm sorry to jump in when maybe it is none of my business, but I feel I have to make an observation, as an interested SLF based in HK...
I am an expat in the sense that I moved here from the UK for the employer I now have (a big multinational). However, neither I, nor any of my "expat" colleagues get housing allowance or cost of living adjustments, and roughly 30% of my "pay" is "incentive" - dependent on the results I deliver. My salary is totally in line with what my "local" colleagues get.
The days when "expats" got special treatment, at huge cost to their employers, simply because they were "expats", not because they were inherently any better at the job, are pretty much gone in every other industry - why should flying planes be any different?