Sorry, did not see this thread earlier, but posted something similar here over a week ago.
What seems to be happening is that there is a confusion between dollars and kWh. If you disable “show cost”, it will graph kWh values on a “Dollar” y-axis. Quote: "If I enable “show cost” in the settings, it’s all in dollars and looks fine. If I disable “show cost” again in the settings, the problem comes back.
If “show cost” is disabled, there should not be any dollar axis. (The app is correct., the web interface not)