A 15% bar tip is high? Not in my book.
Remember, the $10 per day isn't just for one person, it's for 3 folks in the dining room, your room steward, etc.
As others have said, you can adjust the $10 per day if you feel the service wasn't good.
Carnival Elation March 11
Carnival Imagination Sept 07
Carniival Sensation Dec 06
RCI Sovereign of the Seas Sept 06
Carnival Miracle Sept 05
Carnival Glory Sept 04
Carnival Fantasy Jan 04