Yes, we were 5 ppl inside room on Fantasy last year....my bf's 76 yr old dad slept in the roll away that was actually down on the floor, we had the bed & the kids had the 2 upper bunks. We didn't mind as we don't spend any time in the room except to sleep & dress. Guys and gals had equal time for dressing privately. Yes, that's how the pricing was done with us.
There are certain ships that allow you to have five to a cabin. The pricing is the same for the 3rd/4th/5th passenger. To my knowledge the fifth bed is always a roll away. We were fine with four adults in a cabin and fine with two adults and three kids, but I think five adults would be pushing our luck.