A cat. 4 sleeps 4-5 people and is 304 sq. ft. These rooms are only on deck 8. Cat. 5's sleep 3-4 and are 268 sq ft. These are on decks 5, 6, and 7. The verandahs, if I'm not mistaken, are the same size. The cat. 4 has a pull-down bed, causing the room to be slightly longer, giving it the larger square footage.
HTH!