I can't understand why there should be a daily service charge €7 per day over and above your initial payments when it's a compulsory expense !!! and to then be charged 15% on all extra's seems a little underhand to me.
Other services on the boat such as sauna and massage are alo expensively wrapped up in packages and day rates (€33 I think) when you may only want an hour or a brief escape. Internet access was also expensive at €26 for 3 hours.....even McDonalds give this free.
You should also be aware of port to city transfer cost particularly in Marseille