Service is not included in the cost of anything. The price you pay for the holiday is not inclusive of service so you pay 15% of every bill for service (regardless of whether or not you were actually 'served'!) and I was completely thrown by the fact that gratuities are compulsory if you opt for the 'My Time' dining option, costing an extra $70 per person. I actually would not advise the 'My Time' dining option, as it's really hard to get a table unless you book in advance. The set dining times actually provided greater flexibility and it costs less.
The ship details the price of goods and services, without service and tax, so the actual cost is much more. The cheapest bottle of wine was about $33 (for a cheap £6 bottle of supermarket wine), but the real cost is $43 by the time you add service and tax. Alternatively you could get a tiny thimble full of latte for $3.50 by the time you added tax and service. I just couldn't enjoy it when I felt so ripped off. I don't mind paying for great goods and services, but it doesn't feel nice to pay extortionate prices for very ordinary things.
I purchased a bottle of vodka in the onboard shop and was told that it would be confiscated until the last day of the cruise!! Similarly there were several notices saying that alcohol purchased in port would be confiscated for 'policy reasons'!!
So, the ship was great and we did have a nice holiday, but would I cruise Royal Carribean again - not a chance!