Commentary for Futonggu KID-20
All the Kidney points on the abdomen (from Henggu KID-11 to Youmen KID-21) are also part of the Penetrating Vessel. Thus their indications are related to both the Channel and the Vessel.
The Penetrating Vessel is the 'Sea of Blood', 'Sea of the 12 Channel' as well as the 'Sea of the abdomen avenue'. Thus its points are often able to invigorate the Blood and Qi and remove Stagnation, especially in the abdomen.
As for Futonggu KID-20, it is not a major point. Its main action is to regulate the Middle Burner, open the chest and transform Phlegm.