I am working in Vietnam as well and I can confirm the last 2 posts are pretty accurate. The way they do business here will not change in the short-term because that's their culture at the moment. Nobody cares, not in VNA, not in VJ, not in Jetstar and not in Bamboo. Companies are milking cows for the management, either through cadet programs, captain upgrades, fleet transfers or instructor upgrades. But I think in the last few years they really went into overdrive. If someone doesn't need money and really wants to come to Vietnam then I guess 4/2 schedule in VNA is the best option, provided you don't need money and you don't care about anything else.
Airline business is no different than any other business in Vietnam, you pay - you can do. You do not pay - can not, can not.