Roller Shutter down via Astro-Binding Channel "civil Dusk" -> adjustment necessary

Hello everyone,
I have a rule based on the astro binding (Channel ‘astro: sun: local: civilDusk # event’ triggered START), which ensures that the roller shutters go down at night. Now it is so that - for my wife - the shutters shut too early for “Start” and too late for “End” :face_with_raised_eyebrow: :zipper_mouth_face:. How can the rule be set to 10-15min “after start” or 10-15min “before end”?

Here is the complete rule:

rule "Rolladen runter bei Sonnenuntergang"
when
Channel 'astro:sun:local:civilDusk#event' triggered START
then
if (Rolladensteuerung_AnAus_Switch.state == OFF) return false {
    Rolladen_ALLE.sendCommand(DOWN);
    Rolladen_Hauswirtschaftsraum_BlindsControl.sendCommand(1)
   }
end

Not the rule, but the Channel of the Thing, just define an offset:

grafik