WTH can't I use opower to populate the energy dashboard in concert with a solar system's sensors

Sort of related to the “nested” entities in the energy dash here: WTH: Why can't I nest energy consumption
I’m pulling data with opower, it tracks farther back than my solar system’s data, but it doesn’t capture solar generation, just net consumption.
I’d like to be able to overlay the metering output from my inverter’s sensors to actually see total generation. but if I try to use both right now, they’re applied as additive and mess up all the readings.
I want to see both to compare if my utility is matching what my solar setup is outputting, but I can’t right now.