Just a thought on strange ticketing pricing on BKK route:
I recently booked a europe-BKK ticket because I had vouchers left to blow (plenty of J upgrade space on HEL-BKK flights recently)
The price for economy classic was 740€ return, premium economy was around 2000€ return.
I booked the 740€ economy classic ticket and went straight to check the upgrade cash prices: 145€ to upgrade to premium economy one way.
So that would make it 1030€ to buy a return economy ticket and cash upgrade to premium economy or around 2000€ to buy premium economy outright.
Very strange pricing. Who would buy premium economy tickets when you could just buy economy tickets and upgrade for half the price?