Yeah, I've noticed this too. I don't know if it's a bug or by design, though. Then again, it seems that the actual damage of a lot of the shaman magic spells bears little resemblance to the quoted damage in the (wholly inadequate) descriptions. Insect Swarm's a prime example. From the description, you'd think it only does a few points of damage. When it actually is one of the more effective spells (cause it does that damage over and over and freaking over).
A detailed description of what all the spells (and skills in general, really) do would be most welcome.