Before final payment they will honour the price drop but you will have to factor in any included packages or non-refundable discounts from your initial purchase. After final payment, if you have booked direct or with a PCC, they will work to compensate you in some form or another. That has not been my experience with a TA, however. Also, booking with a PCC/direct is the best way to receive upsell offers closer to the sailing. Again, that has not been my experience with a TA, so I prefer using a PCC.