Staterooms big enough for 4?

[KaTFacer]

I tried to plan a cruise right now with some friends, and when we looked at the prices for three people total, we saw a cruise that caught our eye. They have four people so we changed the info and now it said there were no rooms left. The website lists the staterooms as being big enough for 3 or 4 people, so why wouldn't they let two brothers, both less than 10 years old, share the extra bed?
When we went on our cruise, it was just my wife and I so we never saw how big it is, but my husband is 6'1 and 250 lbs and he took many a nap on the couch below it. Are there different configurations, some rooms built for 4 while others only allow 3?

 

[chik1987]

They may be at lifeboat capacity for that particular area. Even if rooms can handle more people if there isn't room in the lifeboats they will not allow you to add people.

 

[tigerchic89]

It's because some rooms have the 4th bed that comes out of the ceiling, some do not have that bed

 

[KristiMc]

Some rooms only sleep 3. Also could be that the rooms sleeps 4 but there is not anymore space in that lifeboat or the kids club is full for that age group.

 

[KaTFacer]

Thank you everyone. Asking you guys gave me better answers than what I got from google!

 

[Geomom]

When a room sleeps 3, it has the queen bed and the twin sized sofa bed. A room that sleeps 4 had the added twin sized bed that comes down from the ceiling.