Damage Output of Lightning Recovery (Tome of Battle Maneuver)

Lightning Recovery is a Tome of Battle maneuver that allows a reroll on an attack d20 if it misses, along with an additional +2 on the second attempt. How can I calculate the value of the damage added per round? Here are some figures we can use:

Rapier Attack: +10/+5
Base Damage: 1d6+2
Extra feat damage: 2d6
Critical: 18/x2
Battle Ardor (warblade ability): +2 to confirm critical threat
Target AC: 20

How much damage per round does the use of this maneuver Lightning Recovery add? I’m guessing it’s an array of spread due to the 5e ‘advantage’-like nature of the maneuver mechanic? Could that even be averaged?