[Zubersoft]

You are using the "Scroll to Top of Page" (Nach oben scrollen) and "Scroll to Bottom of Page" (Nach unten scrollen) pedal actions which is not going to work well for what you are trying to do. You must change that to "Nach unten scrollen, am unteren Ende umblättern", and "Nach oben scrollen, am oberen Ende umblättern", and then you'll be able to specify the percentage of the page to scroll with every pedal press. You don't need to modify the automatic scroll settings as you are not relying on those. 

Mike