It's unsure because up until now, many people can still not agree on its identification. Anyway, I'm ok with whatever name it gets.
I have two of this plant. I kept one in Dalat and one in Saigon. Eventually the one in Dalat died on me but the one in Saigon is still growing, although, as you can see in the photo here, one of the growing tips has died.
Despite that, it does bloom when its time come. And here is how it looks, today.
After this flush of blooms, I will repot it. I believe its dying tip could be due to being pot-bound. I hope I'm correct and that it will thrive after that.