Building Height: Overall height from the lowest point of conditioned space to the highest point. Regardless of the projects varying height, and/or multiple project roofs, the building height should just illustrate the height of the project's thermal envelope and not an average. For reference, this is a factor that is used to calculate wind resistance and fan loads in the energy model.
If your project has a pitched roof, then the building height might include this height if the interior space is occupied attic space. If your pitch roof encloses unoccupied space, then do not include it in your building height calculation. In this case, the highest point of conditioned space is the ceiling of the top floor, below the attic space. If your project has below-grade space, do not include height if space is typically unoccupied or not conditioned. Last, in the case where you have a form which includes a type of vertical extrusion, or tower, that noticeably increases the building height input, if that space is occupied+conditioned then you would include the total height; if not, then you would need only input the main space.
This article can help explain why a building height was miscalculated when using the Revit plugin.