I believe on Jan 2nd you'll be able to book for Jan 12th, and so on. Not sure as I've never stayed that long.
What I do know is that if you have a split stay, it's 180+10 from the second reservation for the second stay for the days. Ie:
Stay 1 - Jan 1 to Jan 5: You can book 180+10 for Jan 1 to Jan 5, on July 5
Stay 2 - Jan 5 to Jan 10: You can book 180+10 for Jan 6 to Jan 10, on July 9
Same goes for FP+