Originally Posted by
eternaltransit
So you may be able to upgrade one or both of the W basis sectors but not the other saver fare sectors assuming they are the really cheap savers that can't be upgraded before check-in.
However, if there's two sets of Fare Rules, the most restrictive condition applies to the entire itinerary.
In effect this means that despite one direction of travel not having the "CHK-IN REWARD UPGRADE" endorsement it effectively does, as the other direction of travel's rule is applied.