Actually I did have a comment until I took at look at your screenshot. Normally when I do an upgrade, I have upgrade polices that are created under the normal agent policies... something like "Symantec Management Agent Upgrade", "Deployment Solution Upgrade" etc....
These policies should automatically update the client software like any other software package.
The screen you are showing here, rollout, is what I normally use for one-offs. Not a mass deployment. I'm not sure if that has anything to do with it but I would definately use the policies if I were you.
Thanks,