Sorry waterskier, don't know for sure. I do know that somehow or other US citizens(pilots) manage to avoid paying US taxes so there must be a way around it! The IRA and Roth limits are pathetically low so it can't be through those avenues. See if you can get in contact with someone as maybe they don't want to post on a public forum;-)
Your understanding of HK end of tax is correct but it can take them a few years to catch up with you! The FEIE is $85.7K this year by the way, not that it helps much!