Apogee settings for best hair removal???

I just had my first laser hair removal session at Sona MedSpa. They treated my buttocks area with a 20J setting Agogee Laser. They started at 18J but I convinced them to raise the level which they reluctantly did to 20J. I felt almost nothing during the session. Afterwards there is no redness, swelling etc. It’s like I had nothing done. Are these settings effective?