Originally Posted by
etiene
Airlines can both close and open inventory in specific fare buckets, so having historically found I bucket in February means exactly nothing as regards finding it now. Not to mention that past performance is not predictive, etc. IIRC OP has the original return booking in January, so can't necessarily wait until Revenue Management theoretically open some more space later on before making their change.
The OP can book one of the available options and then keep an eye on availability for a better option. I do think that there may well have been a carrier surcharge change since the flights were booked and if there has been any increase , then that will need to be paid - plus any increase/reduction in taxes that may apply