I originally had a units mismatch between my DGN files which were in Meters and the FloorMaster.DGNLib which was in millimeters. This caused floors that should have been at 135.00 to display as 13500. But after changing the working units so that everything now matches, for some reason the elevation values in FloorManager are changing to what appear to be random values. For example, I have a floor with an elevation of 17373. For that floor I created a reference plane of -185 which equals an elevation value of 17188. But while that reference plane still has an elevation of -185, its relative elevation is indicated at -1720112.000. What could cause this type of behaviour?
You will need to check the resolution of your DGN files and FloorMaster.DGNLib to make sure they match. While it is important that the working unit names match as well, the resolution is used internally to geospatially locate objects, whether an element placed in a Model or the coordinates of a floor.