I had asked the same question but the tech said it was just easier. They were able to install the neurio on the main panel instead of having to run the wires through the conduit from the PW+.Why would you use an additional Neurio when there are at least 3 empty CT channels in the Gateway 2 pictured in this thread? The only reason I can think of is that the distance exceeds normal CT wiring, which probably doesn't apply to this case. The reason the CTs are empty in this case is that the solar production is reported digitally by the Tesla inverter. Adding 3rd party solar would require CT metering to be logically added in the Gateway to the solar quantity reported by the Tesla inverter.