Percentage tracking for Rollershutter that only closes 25% upon DOWN command

  • Hardware: rasperry pi 3
  • OS: openHabian
  • openHAB version: 2.5.3
  • Issue of the topic:
    I am using RFlink to control Warema Windowblinds with openHab. The problem is, when the command DOWN is sent, the shutters only close 25%. If the UP command is sent, the shutter open fully.
    So to entirely close the shutters, the command has to be sent 4 times or in a continuous stream lasting about 30sec.
    Now I want to be able to integrate the shutter control into Homekit, so that I can control them using my phone. However I need the percentage feature to be working in order to be able to integrate them into homekit as far as i am aware.
    What could I do to solve this problem?
    Is there for example a way to create a proxy, which send the DOWN command continously over a certain time period and then acts a a shutter item?

PS. so far I have only had experiences with PaperUI.