( A ) As you know, selections with the Control Line’s picker (like with Control Points) are based on Chrominance and Luminance values, which is why we have these adjustment sliders.
What you are ask for can be achieved with a Control Line.
( B ) The selection with the Luminosity mask’s picker is based on Luminance – hence the name.
To (re)adjust move the picker, use the stepped gray wedge and / or experiment with the values / triangles.
Further corrections (other than repositioning the selection point, size or spread) can be made
(A) with additional or negative Control lines / Control points
(B) with Brush or Eraser (also use its Feathering and Opacity)