He means, when a date opens up on the calendar after being sold out we don't know if that is 1 room, 10 rooms , 50 rooms.There are 100 cabins
I don't think it's the end of the world if it's a few rooms that are cancelled heading towards the 90 day cancellation date. Considering the price it will be hard to fill up on shorter notice, which is why there cancelation policy is 90 days vs 30 days.
However if there are 10+ rooms open on each of those dates then that is a really bad sign.
In the end, I expect we will always see sold out cruises open up around 90 days of voyage because inevitably some people will cancel. For various reasons, including not being sold on the value.