I totally understand your growing impatience (and those of others who are in the same boat), and I still keenly remember how frustrating the wait was for me. Having said that and now with the advantage of hindsight, I think we all need to realize that the visa officers who work at the HKVO (or any other offices) are real, breathing, individual human beings. We like to look and compare timelines, and when some of us seem to fall behind, we automatically start over-analyzing the situation, and fall victim to the fear that something must've gone wrong. But most of the time, that's not the case.
These visa officers are humans, not robots. And as such, it's not hard to see that each individual must have his/her individualized style in terms of case review, and as a result process cases at slightly different speeds. We can't just expect our assigned visa officer to simply drop everything he/she is doing as soon as our supplemental documents arrive, and start reviewing our case. On top of that, don't forget that as human beings, they are also entitled to vacations, sick days, mood swings, or simply having a bad day and wanting to slow down a bit.
This can explain a lot of the inconsistencies in our timelines.
My point is if you're confident that you've submitted everything that was asked of you and done everything you could, then take a deep breath and give yourself a pat on the shoulder. You've come this far and you will most likely make it to the end. The wait is an inevitable part of this process. We ALL go through it. But trust me, once you arrive at the much-hoped-for destination, you will realize that the wait, rather than the end, is what made this whole process so memorable.
Best of luck to us all!