Some people said on this thread that they did get or see good deals on some holidays/Black Friday:
https://boards.cruisecritic.com/topic/2888560-40-off-promo
I do seem to recall seeing something that looked a bit better than usual for President's Day(?) this year. Like people have said, though, there are numerous components to the overall cost so it's not obvious how good a 'deal' really is.