But the question is whether BA did ticket it incorrectly. It may the feature of the booking system that the allowance for the cabin is shown on the ticket but BA check-in agents know to apply the greater allowance for the entire itinerary. To tell you the truth I never saw a BA issued ticket where the baggage allowance was uniform based on the higher cabin. It is always per cabin. Even for solely BA itineraries. Same as the additional EMD allowance is never shown on the ticket. BA agents just know to apply it. BA told me that it was not possible to manually change the baggage allowance and that it is indicated automatically based on the cabin. So, if the rule is what you say it is then PS should have looked up BA's policy, should have looked up the allowance for the 1st segment and allowed 3 bags, right? But I think that it is not possible for PS to look up the allowance of the 1st segment.