My shaman's shield enchant (Korobars - US Madoran) is the +160 intellect enchant, which I have seen give other classes +30 points, but is giving me 0. I compared it to another elemental shaman on the realm and it is also giving him 0. (There aren't many characters with enchanted shields on the realm to compare to at this point).
However, I checked some elemental shaman on various other realms and they are all getting +30 for +160 int to off hand, so it isnt just the value you guys have assigned to it. I figure this is worth pointing out to you guys.