Originally Posted by
bennos
PE is not technically Y, it is W. Passengers ticketed in W but seated in Y would I imagine be entitled to the difference in fare (probably quite small due to the TATL being the main component) for the involuntary downgrade.
If PE is considered a class in itself, then Regulation 261 stipulates a different compensation for a downgrade (30/50/70% of the ticket cost, not the fare difference). We will see.