Hello, very good plug-in, thanks!
I know it's not the right place for that, but I found out a bug. When you move the position of the person below 0 on the y-axis, the height is miscalculated.
Here's a fix at line 616 of HeightMeasurePlugin.cs:
//var footOffset = Vector3.Distance(footPos, Vector3.ProjectOnPlane(footPos, rootTransform.up)) - floorDistanceOffset;
var footOffset = Vector3.Dot(footPos - rootPos, rootTransform.up);