If I am at an all inclusive hotel with self-service buffet for all meals (which is comparable to Royal with Windjammer for at least breakfest and lunch) a few Dollar max. but for sure not that much. If you avoid MDR for dinner in the last years due to the uninspiring new menues and use speciality dining you have to pay tip on top anyway.
Room service has been reduced by 50% and tips have been increased by 50%, that is simply 100% more for the same service…