Regarding critical damage with the revamp

Cyanne, how do you figure that? The damage range numbers make no sense to me at all.

30% on mastery skill has a 423-939 range, 423/939 = 45%
20% on mastery skill has a 329-939 range, 329/939 = 35%
0% on mastery skill has a 141-939 range, 141/939 = 15%

And I'm assuming 370-569 (370/569 = 65%) is with maxed mastery, which gives 50% bonus mastery.