Maybe someone can shed some light. I was looking at EF and see different loads for the same flight. AC 334 on 7/31/21 is the flight I'm on. Shows D2 Z2 P1 R2 Y9 B0 M0 U0.. with my routing, but D3 Z3 P3 R2 Y9 B9 M9 U4.., either as a standalone flight or in a different routing.
