Now any client that connects for updates is seeing not only the latest updates, but all updates leading up to it.
For example, I use Deploy Studio to restore an image of Snow Leopard 10.6.7. I then run Software Updates and get a list of required updates, which includes not just iTunes 10.4.1, but also iTunes 10.4. It also shows Mac OS X 10.6.8 and Mac OS X 10.6.8 v1.1. If I let it go with all updates selected, the update fails; I have to go through the list and deselect the duplicates and/or outdated versions.