World composition and editing level/s?

So if i enable world comp and the map is divided into its levels, can i still make all future changes in the persistant level and they will automatically reflect in the divided levels? Or do i need to make changes specifically in the divided level according to the location i am editing? thanks

With world composition, you must create one terrain block per world composition sub-level.
You cannot (or would not) put terrain blocks in the persistent level.
You do this by creating each neighboring level in the world composition window, which makes each world chunk have a terrain proxy object.

Much of my map is already created , so i am wanting to use the level splitter plugin which will split the persistant level into sub levels as far as i understand it , but either way are you saying then that additions to the map or say landscape changes or adding foliage must be done in that particular sub level where one is is adding or changing things? I mean if you are adding or making changes to a section of the map(sub level) , then that particular area where changes are being made must be current while making the changes? Thanks for reply.