That doesn’t seem consistent with my experience, over 25
DCL cruises. I have never had a problem purchasing a smaller multi-bottle package on longer cruises, even including Panama Canal, Transatlantic, and Hawaii cruises of 14, 12, and 10 nights. They are really multiple-bottle packages. I usually get a 4-bottle package, even on longer cruises. DW does not drink alcohol, so I spread a single bottle of wine over two nights. The assistant server is always happy to close the half-full bottle and bring it to the next dining room. I have even had a bottle from the premium wine pachage opened in Palo and had the leftover half sent to the MDR where we were dining the following night.
One thing I do after the server has poured the initial glass of wine from a new bottle on the first night of a cruise: I tell the server that I will refill my own glass when I’m ready for more wine. Otherwise, they have a tendency to ”top up” the glass as soon as I’ve taken a few sips. It’s real easy to lose track of how much has been poured so you don’t have much left for the following night by the end of dinner if you’re not careful. This only works for red wines, since bottles of white are placed in an ice bucket that’s out of reach. Of course, the server who understands my plan will manage the pouring of white wines accordingly. In Palo, I make my two-night/bottle plan clear to the server, since they always hold the bottle in their serving area rather than placing it on the table.