It might go a little down since it is still very far way. That said if you expecting 159 each way it will never happen.
That time period is the busiest of the year. I would book and focus on other things.
Playing chicken with Christmas vacation prices is not worth it especially if you have huge savings expectations. If you want to save better to compare all other destinations such as Hawaii and other Mexico cities.
If you are flexible early December is a cheap time to go to any vacation destination.