Dynamic Levels?

I have been experimenting with creating blocks with fields, and have found I can use fields to create a block that can actively define levels. By setting up an attribute that reads a point’s value in northings, I can block them together and wherever I choose to put the block, it will give me that value for northings. If I move the block vertically, the northings update accordingly. This seems like a very useful tool to have coming from a structural draftsman's point of view, where I am constantly working with and updating levels on my drawings it would save a tremendous amount of time if cad could define changes in level rather than me having to get the calculator out each time! I’ve attached what I have so far - Dynamic Level.dwg, but what it is desperately lacking is to read the level out in meters rather than millimetres! Any suggestions? I would so love to use this neat little block in my drawings...