Angle definition for "Efficiency upwind" / "Efficiency downwind" in Boat Setting

Hi,In Boat Settings > Polar, there are separate "Efficiency upwind" and "Efficiency downwind" percentage fields (e.g. 100% / 92%).Could you clarify exactly how qtVLM decides which one applies at a given TWA? Specifically:

1. Is there a fixed TWA threshold (e.g. 90°) that switches between the two, or is it relative to each boat's own best-VMG-upwind/best-VMG-downwind angles (shown in the "Best Angles" box)?
2. Is there a hard cutoff, or a blended/interpolated transition zone between the two efficiencies?
3. Does this threshold change with wind speed (since best VMG angles do)?

Thanks!

Hi,
The threshold is fixed and is at 90°
--Philippe