Problem whit Orb of Slow

[Arohk]

Hello, i was trying around whit the orb of Slow ability but i just don't understand how it works, i also can't find a clear tooltip anywhere.

here is where i run in trouble, i tried to make it a Hero ability whit 5 Levels and give it a 5% chance to procc a breath of fire spell per level.

No way what i do it does not work right.
there are 3 'procc chances' to change
http://img517.imageshack.us/my.php?image=orbcw5.jpg

i also tried to set them all to 100 but it didn't cast any breath of fire... never

 

[Captain Griffen]

Hero summoned and normal are the chances.

Orbs are bugged, in that they only work when ordered to attack/attack move, not when auto-aquired.

And they may not work with AoE abilities, but not sure.