I'll just repeat a previous post of mine.
Maybe the new method is a result of the Predator DNA.
Think about it. We have only seen Queens from humans. If the Alien takes the most beneficial characteristics from its host, then maybe a Queen takes characteristics of the Predator reproduction method (born in litters). These characteristics, blended with the Alien reproduction method, result in this new, more efficient reproduction method. Now this new method wouldn't exist if the Predalien were just a drone, as only Queens have reproductive organs. But since this one is a Queen, it used its host's reproduction method to it's advantage and created this new amalgamation.
If we are to believe the Alien is a truly adaptable organism, than maybe it's not to far-fetched to believe that female (Queen) Aliens can take characteristics of its host's reproduction when it would be advantageous to do so. Accept it or not, just a little thought.