Not trying to be smart
BUT, the two contractors are aware of any current information regarding your question, also, if it's not in writing, it's just BS anyway (and it never will be). The system Chief Pilot has indicated in meetings that upgrading to another fleet is possible, my guess is that a person would have to work a while in the fleet you have experience in, then, based on fitness reports and Vietnam Airlines' need for crews (along with a bunch-o-money), you'd be able to upgrade. Also, I don't think they are short captains on the 777, as it is, captains are operating in the left and right seats.