It's also good to keep in mind that:
We all believed CF to gross (though not I) less than Hunger Games but have a bigger opening weekend due to it being a sequel.
The opposite happened instead. It feel under OW predictions, but had great legs and went on to gross more than HG.
Perhaps all that great WOM for CF will result in great numbers for this. If its as good as its RT rating (or hell, just pleases the fans) then we could see great legs here too, this doesn't have Frozen on its back to compete with. Not to mention a shorter runtime (20-25 minutes less) might mean more screens maybe.