Just wondering what the difference is.
I may be a little rusty on this, but I believe that "Successfully Installed Updates" mean that the scripts run successfully, and the patch is installed. The status becomes "Compliant" after the update agent processes/verifies the state of the update.
It may take awhile to see "Compliant", depending on how often you run inventory, and how many mobile devices that you have. (ie. Off-network devices may not run inventory scans)