The coordinates are relative to the model origin which is fixed in space and cannot be moved. All you are doing is moving the axes. The default location of the axes places their intersection on the origin. The intersection of the axes doesn’t define the origin.
The other part is that label text in SketchUp is not dynamic. It is in LayOut, however. If you can add the label there the coordinates will update if you move the model in the model space and update the SketchUp reference.
Yes true, just isn’t practical if all my views are setup.
I don’t mind using Layout to get z-coordinates, actually works really well. However sometimes in client meetings it would be far easier to have a label in the model that would update if moved.
For reference - The project I want to use this on, I would need to move the model 49m above the origin point. In some cases more. That would do my head in