Set only brightness for Tasmota Devices with SetOption20?

I have a number of Tasmota dimmers set up that I have enabled “SetOption20” for, which should allow me to set brightness and power independently. This does work on the tasmota device page (at 192.168.0.xxx), but I can’t seem to set brightness without turning them on in Home Assistant.

I try calling this service in Home Assistant:

service: light.turn_on
data:
  brightness_pct: 75
target:
  entity_id: light.entryway

and get the following MQTT message in tasmota:

22:01:24.653 MQT: stat/entryway/RESULT = {"POWER":"OFF","Dimmer":75}

which I would hope should actually be:

22:01:24.653 MQT: stat/entryway/RESULT = {"Dimmer":75}

Am I doing something wrong here with how I call the service? This has been driving me up the wall! Any and all help would be much appreciated!