poetdante: The chart is wrong. Throw it out, and never look at it again. There are two problems with it,one technical, and one psychological.
Technically the chart is for one handed bullseye shooting. As soon as you start using a two-handed hold, its invalid.
Pshychologically, the chart causes you to focus on what you are doing wrong, which is absolutely the wrong way to get better. If, in your head, you are thinking "Don't jerk, don't jerk" you will jerk the trigger, pretty much guaranteed.
To shoot a handgun accurately you need to do exactly two things: Aim the gun at the right place, and pull the trigger without moving the gun. That's it. Alpha and Omega, Soup to Nuts, Start to finish.
The most difficult part of the process to grasp is that aiming and pulling the trigger are not separate processes, aiming and pulling the trigger happen together, and inform each other.
Again, aim the gun at the right place, and pull the trigger without moving the gun. End of story. everything else is fluff.