Welll It´s my first post and I don´t know if someone already said this but here I go:
The young predalien queen does regurgitate the embryos, but the quantity is restricted (just as a facehuger can impregnate a person with only one chestburster and in the case of a superfacehuger, two chestbursters), and by restricted I mean 3 or 4 embryos wich takes me to that really curious scene in one of the trailers where we see 3 or 4 chestbursters coming out of the same host (Maybe this is Chet doing). And after she has depleted these 3 or 4 embryos that would grow to become her personal bodyguards Chet would loose the ability and she´ll stick to the good old fashioned alien way of laying eggs... but of course after she had molted into a full grown queen...
There you go, that´s my little contribution.