IR and Battle Littany do not increase the amount of Crit you have (ie 500 crit x BL 15% = 575), instead they only affect your chance to crit. So if you had a 10% chance to crit with your normal gear on and you pop BL, you now have a 25% chance to crit. Its done this way because of the 3.0 expansion change to actual crit dmg. Crit dmg is no longer just a flat 50% increase to dmg, it scales exponentially the more crit you have. So if you have a ton of crit your crit dmg may be 54% instead of 50%. If BL and IR increased the acutal amount of crit stat you had, it would be waaaaay to broken.