I know it's an old post, but mathematically its not always the same as dmg.
Eg. Spear gives +35% dmg and plus 5% crit.
Base damage 25.
25 plus 35% = 33,75 base dmg
Plus it does 33,75 x2 = 67,5 in 5% of all cases.
Which means:
33,75 dmg in 95 cases = 3206,25 dmg
67,5 dmg in 5 cases = 337,5...