$980? Usually we have to pay people to fly to PHX this time of year. It was over 40C here tomorrow.

On topic though, I see this price variance of only $100-200 a lot on last minute bookings (more than 2 days, less than 7) that involve US. For example, in late May I needed to be in DC for 4 hours of meetings. The prices were $1684 in economy vs. $1864 in first. I too chose first. Generally on US it's nearly impossible to find last minute F seats for sale less than 2 days prior to departure.