TCAS doesn't do volumes only time to impact.
Slow things small volumes
High speed huge volumes.
its not a clue where it is operating apart from when you climb through 900ft on the rad alt or decend through 1100ft when it kicks into a different mode.
As for company procedures there is alot of fannying about changing between high/low 5/10/25 mile ranges on the display but that makes cock all difference in the way the unit operates as much as some pilots would like to think otherwise.