Window / Cover time_based with offset

[mhoeneveld]

I have an interesting issue that I could not resolve yet.
I successfully implemented a a time based cover steering. It is running now for several days and works brilliant.
However, one thing intrigues me. To open the window it first unlocks which takes about 4 seconds and then starts to move the window. The cycle from pushing the open button till 100% open is 39 seconds (so 35 seconds the window is really moving)
In my home automation I set (depending weather conditions the window in positions 25%, 50%, 75% and 100%.
The time_based cover component takes thus 39 seconds divided by 4 for each 25% opening position.
Closing the window takes 35 seconds and then it starts to lock itself. However to keep the moving open en close synchronised I defined that to 39 seconds as well. (Otherwise closing and opening a 25% step a few times during the day would slowly keep the window further open each time by approx. 10%). But this results in the effect that when closing from 100% to 75% the physical position is 85% and so on.

Now the question. Is it possible to create an offset of 4 seconds on opening the cover before the time starts counting the position? The open_duration parameter counts for the whole open_action I understand and I don’t know if you can perform a 4 seconds open action before that.

I know it is not a major issue but it keeps me busy thinking about a smart solution for it.

cover:
  - platform: time_based
    name: "${cover_name}"
    id: axa_test
    device_class: window
    has_built_in_endstop: true
    manual_control: true
    assumed_state: true
    open_action:
      - uart.write: "\r"
      - delay: 0.1s
      - uart.write: "STOP\r\n"
      - delay: 0.1s
      - uart.write: "OPEN\r\n"
    open_duration: 39s  
    close_action:
      - uart.write: "\r"
      - delay: 0.1s
      - uart.write: "STOP\r\n"
      - delay: 0.1s
      - uart.write: "CLOSE\r\n"
    close_duration: 39s   
    stop_action:
      - uart.write: "\r"
      - delay: 0.1s
      - uart.write: "STOP\r\n"