Here are RCCL guidelines:
Stateroom attendant: $3.50 USD a day per guest
Dining Room Waiter: $3.50 USD a day per guest
Assistant Waiter: $2.00 USD a day per guest
Headwaiter: $.75 USD a day per guest
I did the math and come up with $9.75/day.
The 25 cent difference is because tipping is not required at Johnny Rockets.
I think you are in for a real shock the next time you cruise RCCL.