Ok, @Yna_Db, I’ll bite… I may be misunderstanding your issue here, but I would not go through all that sorting and stacking and intersecting etc. Won’t the point.project node suffice? If I have understood you correctly you can also filter out all the boxes which already have a parameter for excavation date set, right? Then you can try to project all these points toward the toposurface in negative Z direction. If it fails it means that the centroid is below the surface and will return empty list. then a simple sorting and then you have all your boxes above your topography which do not already have an excavation date set.
https://www.dropbox.com/s/rj3q6dx8bvkelav/EarthCube%20-%20Olsen.dyn?dl=0
Also remember the Dynamo/Revit element binding, so that not any parameters are overwritten/deleted etc etc.