More time on holiday weekends

I always assumed that when there's more time than usual on a puzzle/sudoku competition, that it has to do with holidays in other countries. But it looks like we don't get extra time for puzzle round 5, which takes place the weekend with a holiday in the US. Am I wrong about what causes some weekend tournaments to get extended? And if not, can we get an extension on that puzzle round 5?

Thanks,
~DreamRose311