RESTful sensors for Covers?

Hi,

Has anyone been able to use a RESTful sensor-like code in a cover instantiation?

I have sensors that determine the state of an A/C duct (open or closed) and a cover to open and close the duct, but ideally the cover would know its state without the sensor…

The sensor is:

- platform: rest
  name: Zone Green Room # Zone 1
  resource: http://192.168.1.192/Zones1_4
  method: GET
  verify_ssl: false
  value_template: '{{ value_json[0].Mode }}'

and then the cover, using this sensor for its state:

green_room_duct:
  friendly_name: "Green Room Ducts"
  value_template: "{{ is_state('sensor.zone_green_room', 'open') }}"
  open_cover:
    - service: shell_command.ac_command
      data_template:
        data: '{"ZoneCommand":{"ZoneNo":"1","Command":"open"}}'
        url: http://192.168.1.192/ZoneCommand
  close_cover:
    - service: shell_command.ac_command
      data_template:
        data: '{"ZoneCommand":{"ZoneNo":"1","Command":"close"}}'
        url: http://192.168.1.192/ZoneCommand
  icon_template: >-
    {% if is_state('sensor.zone_green_room', 'open') %}
      mdi:fan
    {% else %}
      mdi:fan-off
    {% endif %}

I’m really just trying to improve my cover code style as I’m sure it is inefficient (and I get up to 10 second delays in updating the state on my UI when toggling which I though may have something to do with the separation of the sensor and the cover itself - some is obviously associated with the A/C processing the command).

Thanks for any help you may provide!

Matthew