[Nitram Draw]

I think the way it works is that the filler techs are alway chosen if another tech needs to be researched. So in your example the two filler techs would continue to be the next two techs chosen until one of the other "useful" techs were researched. Then the two filler techs and another "useful" tech would be chosen.
I think you can waste points this way but it does let the AI always concentrate on two techs at once.
At least that's the way I think it works.