counter 3 keeps track of total ticks spent aiming during the match,
counter 4 checks if you actually aim for 12 consecutive ticks without switching target
counter 5 keeps track of how many shots have been fired during the match.
at the end of the match you can easily see how many ticks you've wasted aiming without firing,
[counter3 - (counter5 x 12)]
getting a more precise idea of your aim stability.
hope it can help