Calculations:
Before the patch: (0,2258+0,2258) x 0,2278 = 10,29%
Mastery level 1: 0,1 + (0,46 x 0,27) = 22,4%
Mastery level 10: 0,1 + (0,2 x 0,28) = 15,6%
Mastery level 20: 0,1 + (0,36 x 0,17) = 16,1%
Mastery level 30: 0,1 + ((0,4 x (2/11)) x (0,32 x (8/12))) = 11,5%