How do I sculpt over level boundaries on different heights?

I’m using the world browser and its tile system to create landscape. Sculpting from one level over to the other works just fine, but if I have the level higher than the other, it will sculpt with the same height on both layers as if they where on the same height, resulting in them not really being on the same height due to the other one being higher. And with higher I mean like +200 on the z axis of the landscape proxy.

Anyone have any ideas how to create landscape smoothly with the levels being on different heights? The reason I am doing this is to create mountains that are 2-3 km in height. I have my z scale of the landscape set to 390.636932 which is exactly 1 km high.