Backwards Mass Times Explained

So I posted earlier about the odd Mass times for New Year's Day.  Today I tracked down some members of the Parish Liturgy Commission at coffee and doughnuts after Mass to ask them about it.  (And was amused when two of them had no idea.)  I got an  explanation though; turns out that New Year's is not a holy day of obligation this year.  So the 9am Mass on the 31st is actually the usual Friday morning daily Mass, and the 5pm Mass on the 1st is the usual Saturday evening Mass.