So like I was predicting and like rtalk25's experience, WN fares dropped so I tried to call change my itinerary to another flight to TPA in October. I was told that they couldn't do that without redepositing the points (for free because of a schedule change) and that I would then have to pay the less than 180 days award fee to book the new award flight . Their own website clearly says itinerary changes >7 days are free if the class of service is still available. Per the agent I was talking to they can change the itinerary but only between the same pair of cities. It looks like what I'll end up doing is booking my award flight for the farthest out I can when they extend the schedule for the city pair I want, and then request a change to within the 180 days. If it worked for United it should work for Frontier.