The weekdays have been good. Not amazing, but this isn't the time of year to expect great weekdays. Look for it to remain incredible strong on the weekends while the weekdays stay relatively average/normal until the last few days of the year.
However, films that go on to have phenomenal runs (around the multiplier of 20 ) do often post excellent weekdays despite the time of year, so I'm starting to believe Frozen II won't have a phenomenal run. It's clearly still going to put up a massive total that could crack the All-Time Top 5, but we can likely rule out a multiplier of 20 for example. It'll likely fall inline with more traditional uber-blockbuster films with a multiplier around 12 or so (a 12 gets it extremely close to ¥20 billion/$180M).
As for a third weekend prediction, a number around ¥1 billion (as cannastop suggested) sounds reasonable, and attainable. So, it should be aiming for a spot in the Top 5 Biggest Third Weekends.