LumenRT Scene "Design Cube" Limitations, can it be made bigger?

So recently I have embarked on an Underground LumenRT VR Model for a mining project and so far so good... until I noticed I maxed out the size of the scene in LumenRT, now in press releases it does mention 50km2 of possible model space but that only applies to the X and Y dimensions, the Z Dimension is limited to roughly 1km, so what I have is a mining model where LumenRT's lowest point when manipulating the terrain is not low enough for me to match the mining models natural ground level with that of LumenRT's . is there a possibility to increase this to possibly having the terrain being able to be pushed down about 2km?