Unable to simulate and check LTC3305 (battery management system) chip algorithm for balancing lead acid batteries in simulink while discharging the battery pack?

I was trying to simulate LTC3305 algorithm in Simulink. I was successful in simulating it and getting the satisfactory results i.e balancing operation (by giving different initial SOC levels to each cell in the battery pack)  when battery pack is neither discharging nor charging. But, when i was trying to simulate in while discharging the battery, balancing operation is not taking place and battery is just discharging.Somebody please guide me .