The reason why you don't see the `Preferred` score in the table above is because we want max quality anyway. So set it as high as possible.
The highest preferred quality you can manually enter is 1 less than the Maximum quality. If you use the slider, the preferred quality can be up to 5 lesser than the Maximum quality.
Make sure you have enabled 'Show Advanced' in Sonarr, if you don't see a provision to enter the scores, under the Quality settings.