A class availability question
 

Perhaps someone can help me understand. I see this on several CX flights, certainly 830 and 840, as well as the trip I'm trying to schedule right now.

I'm looking at a BKK-HKG-PEK connection for next May 8th. (All data comes from EF.) For the CX 750 to 312 connection, 750 shows F4 A1. But for the CX 750 to 6892 connection, 750 shows F4 A4. Same day, same EF display.

Any ideas?

Assuming both flights have three classes (for CX/KA - they use the same booking classes), if you are doing a transit, the availability is limited by the lower of the two segments (or up to the max number for that booking class).