Sir, I do not know what post or operator do you work for. However, once the FL180 is in your approved manuals I believe it is binding no matter what anyone thinks.
So far you have not told wheter you operate under FAA, ICAO, JAA or other framework. Until then it is complicated to come up with any more relevant ideas.
If you are trying to find grounds for not obeying certain requirements or justify some operation that cuts corners, as a crewman I cannot relate to or take part at that. And no aviation professional will.
Just my thoughts, fly safe.
FD.