Does anyone know the reason behind differences in spell range?

I ask because the minimum range seems to be 3.

Now I wouldn't be asking if it were'nt much of a change, but witchdocters get 9 range on 3 range spells. I'm not complaining. But I was looking at my friend's powers and that assassin's stride has a movement of 9 spaces, while on mine it says 5.

Can anyone explain these differences? Especially that Assassin's stride? It just doesn't make sense. Also, my friend hasn't trained in Witchdoctor at all. Someone please help me solve this conundrum!