ALL FOOD, whether self serve or served at the table will have an automatic 15% gratuity added to the bill.  There are rare exceptions to this, so check your bill carefully before paying.  Gratuities are usually included.  This also holds true for Atlantis Pre paid meal plans.  The 15% is added to the VALUE of each meal and presented on your bill at checkout.

This is not unusual in the Caribbean, but something to be aware of.