This paper presents the design of coordinated controller design for boiler turbine units and decentralized controller design for a four tank system using Biogeography Based Optimization (BBO) technique with regulatory effects and set point changes in dynamic system. A complete analysis for each technique is presented in time domain. Performance of both controllers is examined and control performance measures for common input changes. Integral Square Error (ISE) is used as performance index for designing the controllers. Finally, a comparative assessment of each controller on the system performance is presented and discussed. The BBO results give better performance in servo and regulatory responses.