Your first example has 121 hits generating 15 crits in total or a crit percentage of 12.4% (the first 50 hits only produce 5 crits, not the expected 9)
Your second example has 11 casts generating 2 crits (or 110 hits generating 20 crits) which is a 18.2% crit chance.
Why is it so hard for you to understand that these two percentages are not the same and so make your 'example' meaningless?