I was wondering when NCL offers it's double up special for cruise next certificates, is it only when you book a new cruise? Do you see the special on their website where all the specials are offered ? I was able to use 2 certificates per cruise on 4 cruises that were cancelled due to covid, but since then, I have only been able to use 1 per cruise on all my upcoming cruises. Now I have 4 left that will be expiring by the end of 2023.