We were on the Island in October, not our favorite ship. I asked head waiter in MDR for the same table every night at 7:30 and was able to do it. Had the same waiter each night and had our bread and breadsticks waiting for us when we showed up. His assistant showed up a couple of minutes later with our drinks without us ordering them. We let the them know if we weren’t going to show up the next night so he wouldn’t hold it.
We never use the app to order drinks, direct from the bar is quicker. Have had that problem with the 15 drinks when ordering 2 at a time, but if you clarify it with the bartender when ordering they will make sure to separate them.