How would you read these fare codes?
Seat map shows 4 available C seats.
.bomb shows:
F4, FN4, A4, ON3, O3, J8, JN8, C8, D4, Z4, ZN4, P3, PN0, R0, RN0, IN0, I0
So I interpret this as:
D and Z are the actual number of C seats available as they align with the seat map (4), but once those are gone, UA will sell you a J or C seat and bump someone else into F in order to make another C seat available.
Does that seem right? I have no other way to explain this.