It changed in early March. I was going down there regularly on the SEA-LAX-MEX daytime flight with the same flight number all the way through, and then it disappeared.
I ended up taking the red-eye last week just to find the aircraft on the SEA-LAX route was late arriving into SEA. Despite assurances that the LAX-MEX flight would be held for us, AS denied us boarding despite being at the gate 10 minutes before departure. Ended up going to GDL and then Aero Mexico to MEX arriving about three hours late.
So, beware if you do that red-eye.
In addition, AS moved up the AM departure to 6 something AM instead of 7:40. That also sucked in my book so I took the 1:30 PM flight instead