1. I wish we upgraded to a smart aircon controller with multi zones. The 2 included zones are not that flexible. I called an aircon company to ask how much it will cost to add a smart controller to have flexibility of multiple zones. they said it will require updating the ducts and would be very expensive. The smart controller is expensive ($2k+ I think) but then so would redoing the aircon ducts. There is a $300 controller that I researched that is easy to install and gives you access to turn on/off the aircon from your phone but you can’t do different zones.
Also which private certifier did you use?