Found "upstairs" system is mainly ducted for the left bedroom side of the house and there are only 4 total supplies for the upstairs. These ducts are insufficient for the total load of the space and are also located in very inefficient places for cooling the upstairs space. Given the age of the system (2000) my recommendation would be to abandon that system from the upstairs and seal the ducts for the upstairs grills and install Mitsubishi minisplit systems on either side of the upstairs to help with on-demand heating and cooling of the space.