Welcome to FT.

You're not the same user here are you? Also traveling from Boston but going to Phoenix

From what I read online about airfare, there may be times when the prices take a dip on Tue or Wed afternoon. I witnessed this myself as well yesterday when the price for one of my travel dates decreased. It's back up again this morning.

If you read further down that post, sfozrhfco said that you can change the itinerary and get credit for the difference. I wasn't even aware of that but will try it out in the future. Also sign up for yapta so it keeps track of price drops.