Last year when I was planning our May trip, I also was looking for a BOG ADR less than 180 days out. I checked often, even when I would wake up during the middle of the night and unable to sleep. One night a whole bunch of reservations opened up--for dates throughout our trip! I also recommend checking the day before. I think people often give up ADRs at the last minute, so keep an eye out. I ended up switching our original reservation for one that better fit our schedule this way. Good luck! I hope you get it!