You can install our site as a web app on your iOS device by utilizing the Add to Home Screen feature in Safari. Please see this thread for more details on this.
Note: This feature may not be available in some browsers.
I seem to remember solving this problem in the past, but when switching to Scheduled Charging from Scheduled Departure, the relevant options on the screen are grayed out.
If you were plugged in and scheduled for departure, I would think you you would need to unplug to end the current scheduled departure. Then set up Schedule Charged Start and then plug back in.