Why not just put all the a/t on hold for everyone in your cabin? At the end of your cruise, tip the staff based upon the level of service provided.
What other business that you frequent tells you how much to tip? Cruise lines, simply feel the need to augment their staffs compensation with our money. I actually embrace this strategy but I have a real dilemma with a/t based upon some preconceived notion fine-tuned by the mkting. dept.
I know, I know, some people don't tip at all & the staff, rightfully so, relies on these funds as a material portion of their compensation. This is a fiscal responsibility my wife & I choose not to bear.
We usually tip far more than the modest guidelines. We simply tip for the expected service. Most times the service is outstanding & the compensation reflects this. On occasion, service was significantly below what we expected & thus our tipping was more modest.
In any event, proceed in a manner that you're most comfortable with. I'm sure, given the proper amount of thought you'll reach the appropriate decision.
Have a wonderful trip!