it does appear to be a typical product for zoning applications. a zoned system can be implemented in the original design or used to split a single system into two or more zones with separate controls. the latter requires evaluation because it's not just a matter of controlling airflow. the refrigerant system and heat load has to be a match. if half the airflow is cut off, there is an imbalance that defeats the design of the system unless steps are taken in the modification to prevent that imbalance. if it's not modified correctly, it can damage equipment and the balance you are after will not be attained. although it's possible to make such modifications, not every situation is a good application for zoning. as mentioned, hot air will naturally rise and colder air naturally falls because it is heavier. sometimes adding volume dampers at the plenum (for air balancing) can be a simpler and more direct approach and may be all that's needed. again, a qualified person can better advise you after evaluating the entire system. it's possible the system was not designed properly to start with. good luck.