I am not in a position to test at the moment. You could try doing this to manually change your supported modes and see if off then shows in the scheduler.
That driver is out of date, and its author should update it.
The supportedThermostatModes and supportedThermostatFanModes attributes have bad values. For each, the individual words need to be in quotes. To fix it follow these steps:
Temporarily change the driver to Virtual Thermostat, hit Save Device. Then put this string in the command box for setSupportedThermostatModes
["auto","off","heat","emergency heat","cool"]
and hit the command button. Then put this string in the setSupportedThe…