To be precise, Crew Appreciation is the former auto gratuities billed to the cabin account nightly and you had the option to pre-pay via the Cruise Personalizer. These monies are for cabin stewards, dining waiters and other behind scenes personnel. The daily CA is included in Plus & Premier. If a guest doesn't have Plus or Premier, they pay directly, but there is the option to remove all or a portion of CA in this case (not with packages). Most of us on here frown at a suggestion to remove CA if allowed to do so.
For bar service and other similar, there is 18% automatically added to every item and this is not optional and cannot be removed. If a guest has purchased a beverage package, then every ordered beverage under the package comes with no extra gratuity charge because the package cost has 18% added to it. If a guest has Plus or Premier, they have a beverage package included and therefore the bar gratuity of 18% has been included. Notice this is something separate from the CA.
Finally, if a guest orders a beverage outside the package coverage, then they pay the full cost and the 18% (example would be ordering a beer when guest has a non-alcohol package). If they order a beverage that would fall in the package, but is over the maximum cost allowed (e.g. $15), then they pay the difference between the max limit and their drink, plus 18% on that cost difference.