Can it be a Text entity? The first one i am thinking is the Leader Text. That way it could stay attached to a point so it could indicate informations about specific geometry. The normal Text entity which is not attached to any geometry could also be an option for displaying some overall parameters of the whole model. So i think both of these type of text are usefull.
For example it could be an interactive tag but the words "Gross Floor Area, Floors, Building would be just custom text which is user defined. The numbers however could be parametric. For the number of floors it could count the number of components with the same name defined in the Entity info. To differentiate between each floor when they are unique it could take the Definition name of the entity. This way it could also count other user defined objects and components so it could create schedules. It could also do some length computation to calculate heights, perimeters, etc.
Maybe this tag should work when is attached to master component/group which contains all the other sub-components to be computed. So it could work backwards in the hierarchy analyzing what is inside.