Hi @Wingz4life, great questions! I know you connected with our support team Saturday, but I'll share our feedback to your questions here as well:
There are two things we take into consideration when answering questions such as this one: water pressure and electrical current. When you open multiple valves as a part of one "zone," the water is being channeled towards two different outlets, resulting in a decrease in water pressure, which means that both areas aren't being watered as efficiently as they could be. Also, to open a solenoid valve requires a certain minimum of electrical current, and splitting this across multiple circuits can result in a decrease of current to both valves.
Additionally, please note, mixing zones can cause calculation errors in the water volume -- a custom nozzle might need to be setup to properly reflect the actual water use of a shared zone.
No, sorry. The algorithm we use takes the nozzle information from the zone setup to calculate your precipitation rate. Please note that the water flow volume (number of heads) is not the same as precipitation rate. For more information, please see our support article on precipitation rate. We recommend creating your own custom nozzle(s) if you know the flow rate for your zone(s).
Hope this helps. Let us know if you have any additional questions. Thanks again for purchasing our controller!