You can see the confusing effect here https://bertt.github.io/cesium_3dtiles_samples/samples/1.1/delaware/
In this sample I’ve used maximum 1000 buildings per tile, resulting in higher z-levels in urban areas and lower z-levels in rural areas. User can get the impression there is nothing in the urban area, but must zoom in more to show the tiles with higher z-levels.
I think it’s more predictable (in this case) when the display of the tiles is only depended of the distance to camera/geometricError (and not also on the Z level of the tile).
It would be nice if there is a parameter (in CesiumJS?) like geometricErrorFactor.