Simple solution dont fly TCX, we did last year but the tour operator (which is part of the same group) gave us 20kg included whereas people flying on the same aircraft but booked with another tour operator (also part of the same group!!) only got 15kg.
This year we shopped around now going Jet2 with 25kg luggage and prebooked seats cheaper than we could have flown with TCX with only 15kg and no seats
Airlines count on people not doing their homework, you wouldnt get your car fixed at the first garage you get a quote from so why wouldnt you compare details on what is one of the biggest purchases you make every year