I guess, what you ask, is actually part of my question. Why did "they" precamber the slab? Most likely just to have a flat condition at the start of live load application. This would be a similar case to using cambered owsj. As you noted, the cambering will have nil effect of finishes etc. and I...
Does anyone have any guidelines for the determination of camber for a two way slab. I have seen it done but I have not personally done it. I cannot find it in a code or any other reference that I had. I would have thought that the long-term calculated deflection value would be suitable at mid-slab.