There is no valid code "GG", but there is a valid code "G" for box 12. Both of those indicate tax deferred retirement contributions. I've never seen both codes on a single W-2, as they are two different types of tax deferred retirement accounts. You sure you typed the codes right in your post above? The double "GG" just isn't valid.
I'm starting to think your W-2 may be messed up by the issuer.
