There are only 8 million or so combinations, so if there are more than that many quick-picks taken, some must be duplicated.
I imagine quickpicks are generated randomly or pseudo-randomly. Maybe there are certain combinations that quick-picks won't generate, such as 6 sequential neumbers. I can just imagine some people asking for their money back if given 1,2,3,4,5,6 for example.

Rather than go for quickpics, maybe you should try to guess unpopular combinations. Shouldn't be too hard.