Google Tiles vertical placement

Strugling to synchronize google 3Dtiles on cesium.js with terrain and 3D buildings within our application. As a result we have a gap for our city on Z coordinate around 40 meters. What could be the reason for that ?

see Adding objects to Google Photorealistic 3D Tiles | bert

Thank you Bertt - this is what we suspected. You are proposing to recalculatie Z coordinates of building (in fact - terrain. Lidar and all the layers we have in the complete model).
Is there any way to manipulate GoogleTiles in a sense of vertical placement not to affect whole the city model we created

Realize that it can be tricky as there is a need of recalculation on the fly of all dense nodes of the mesh (if possible at all)