Neither do I. We weren't exactly able to ask Qi Rong before he, uh... lost the ability to speak.

[ he clears his throat a little... it's the best way he could phrase that without giving away too much. ]

...My current theory is that perhaps the first set breached their contracts in some way, and the second figured out some sort of loophole that required them to take on those particular positions in their place. Doing so would allow the first set to remain safe... or incapacitated, in the case of Qi Rong.