Asymmetry
Prof. Roger Grundmann (TU for Aerospace Engineering Dresden) had tested and proven this principle with square bows for French horns or bassoons (a short article on this here). We completely redesigned the rotary valve section based on his ideas.
The asymmetrical arrangement means that a sound wave can form more easily in the instrument – which results in an easier response. This still leaves a pleasant blowing resistance, which means that instruments with this valve section are easier to play overall and yet more controlled.