Bottom line is, if you own any previous extra AD1 content (ie. adpaks, kitpieces), you need to choose one of the 2
upgrade offers to get all of your AD1 stuff upgraded. The other Holiday offers are not for this purpose and will get you AD2 content only.
And yes, I agree it's not stated very clearly. With all the Sonar X3 users who have gotten AD1/AD2 bundled, this has and will cause a lot of confusion when they try to upgrade.