How do you know 90% of the seats are sold. Are you looking at Feb school vacation weeks? I have found that when the flight schedule opens up the Wanda get away fares are sometimes not available right away but when the flight gets close and there are seats not sold the Wanda get away fares open up.
I would think adding flights would be difficult thing to do. It would be much easier to switch out a 737/700 plane that seats 143 to a 737/800 that seats 175
