Homekit Rachio integration - how to set duration

In an effort to reduce dependency on the cloud I use HomeKit to integrate Rachio. Zones show up as switches, which is fine. In the HomeKit config (homekit_controller-entity-map) I see Set Duration however I don’t see a way to set this in Home Assistant. When I turn on the switch is runs for however long the zone ran last time. Is it possible to set duration?