I am not a newbie, have done 37 cruises with Princess and have done many using FCDs. In September 2022, I paid 2 x FCD (self and wife) to use against a future cruise. I wanted to use the benefit of the OBC on a longer cruise with a balcony cabin to maximise the amount I get. We booked insides for a 10 day for March next year and another 16 day afterwards. Princess decided to use my wife's FCD for the 10 day but not mine which was not considered at all. I did not ask them to do this and they didn't tell me it was done. If fact, the deposit part was not used at all as it was a special £1 deposit promotion. My intention was always to find a better offer and cancel them so losing only £1 deposit. We were then offered balcony cabins for the same trips through a TA and Princess decided to use my FCD for the longer trip to give me a $100 OBC. Again, I paid a deposit so the pre-paid deposit was not used. I was OK with that so long as the deposit I had paid was taken off the final payment. I wondered mhy they did not do the same with my wife's FCD which was when I discovered they had used it on the prior booking, which was when I was trying to cancel that booking and lose my £1 deposit. Is this a change? Does Princess now choose which cruises to use the FCD rather than that right be retained by the purchaser? I have seen nothing in any terms and conditions saying this will be done.