yeah its 5% chance, but u should edit this bar:
<table name="#chance"> 2 2 2 3 3 3 4 4 5 5 </table>
These are lvls (10 from this skill) and the chance value.
but 5% i think is high chance for a high rate server(u have high rate server right?)
change it to 2/3% better.
and set
<set name="activationChance" val="5"/>
to back like this:
<set name="activationChance" val="#chance"/>
hope i helped