Knowledge of the actual occupancy of a building is a main research interest for several domains. Building energy performance simulation software considers occupancy through the use of diversity profiles usually contained in predesigned templates. This paper aims to explore the extent of possible discrepancies between standard predefined occupancy diversity profiles, profiles extracted by business process modelling, profiles generated from real on field occupancy measurements. Occupancy measurements are obtained utilizing a novel robust, highly accurate real-time occupancy extraction system which is based on a depth cameras network. Results show that the incorporation of real accurate occupancy data, the appropriate understanding of the business processes that take place in building spaces have the potential to significantly enhance current Building Performance Simulation (BPS) software tools.