Bigsky, it depends on the ship or job environment
The auto added bar/drinks 15% for tips, is a share amongst all bar staff, drink waiters etc
Dinner service, is personal choice, tipping level is your choice with the envelopes at the end of the cruise that you hand over going direct to the person
Cabins Cleaning, again personal choice of tip level and the envelope at the end of the cruise again going direct to the person.
Personally I pick out bar staff that have made my cruise and hand over a few bucks extra to them over and above the pool system.
Hope this basic explanation helps more and answers your concern