Re-posted from an EF post years ago -
- Married segment logic applies to fare classes and award classes, as award classes are ticketed as combined segments the same way paid tickets are.
- Married segment logic does not apply to upgrades, as they are processed segment by segment
- The AA host/GDS still applies married segment logic to the C class availability results because it just sees it as another fare class, it doesn't "know" how it's really used.
Therefore, you should search for upgrade inventory segment by segment