I have been incorrect about this for quite some time when testing that skill.
The skill description we currently have is correct and states that the cast time influences the damage output.
The range between character and target doesn't influence the damage output, at least not on the version we currently have.
I apologize for causing confusion about this. The current configuration we have reflects correct behaviour from kGE.
It seems that the range factor is from a higher version but I can't certainly say on what version that changes, it must be some V32.* though.
Hint from a player: Range damace increasing factor can be family attribute and not skill itself.
Please check if you have it enabled, most likely you don't which is why there is no differenge due to range.
