Slicer Heart - annulus angles in valve quantification

Operating system: Windows 10
Slicer version: 5.2.1

In the SlicerHeart Valve Quantification module - there are several measurements made regarding annulus angles (bending angle, etc). How do we find out how these angles are calculated? We are wanting to use these quantitative results for analysis - but aren’t sure what to compare them to since we dont’ know how they were calculated.

Thank you!

Also - follow up question: how come sometimes the billow and tenting height are calculated and other times its not? Are there detailed instructions for how to use each component of the slicer heart module? Thank you!