Cannot seem to get good latency numbers!

Thankyou!
I figured it out and just for the novices to LinuxCNC like me, I am adding screenshot as how to do it.
 

After saving the file you must execute command:  sudo update-grub

Note: I have added myself to root group. I don't know if it had played any role in it or not so if you get an error of permission get added to root group.

Now the latency is as below:
 

and graph is like:
 

 

Still a long way to go but then "Every long journey starts with the first step" --- Chinese proverb. )

Great work. Now you have done it the hard way, type:
sudo grub-customizer and edit/view the same field on the second tab.