When a ticket is purchased before the transportation commences or is reissued according to Rule 255 (Rerouting), the fare applicable to a round trip between 2 points over the lines of one or more carriers will be:

1. When specifically published via the desired routing, the applicable round-trip fare published by or on behalf of such carrier(s).
   
   
2. When not specifically published via the desired routing, the sum of the one-way fares applicable to the respective one-way segments or the sum of the round-trip segment fares if these are published.