Well, I'm new (here) and I see only one person took a stab at this. If I may. . .
Calls and plots is a self diagnostic tool a shooter uses to gauge proficiency and performance.
Your shooting eye (both ideally) should remain open during the entire shot sequence. You should remain focused on your front sight (or scope reticle, dot, etc) as the rifle/pistol/shot gun goes into recoil. This is act of making a call.
If you are at a range where someone is pulling targets for you and using a shot spotter you will soon discover that when you do things right, the spotter will be in the vicinity of where you last saw the sight just before the shot broke. This is the self diagnostic.
From there you plot your shots in some kind of log entry book. during slow fire each individual round should be recorded along with anything noteworthy that took place during the course of fire. You'll do this for awhile and patterns will emerge. Things like groups that shift down and right during offhand stages (assuming your a R/H shooter). This means your trigger control is a bit on the aggressive side and you need to either back off or dope the rifle into the ten ring for this stage of fire. (both are acceptable courses of action btw)
When things are going well then it works great, its when you call a shot at three o'clock in the ten ring and it winds up being a flyer out in the seven ring at 11 o clock that you have to worry.
I tell students that the follow through portion of marksmanship is the least important out of all the others, but it comprises 50% of a shot sequence.