I have a similar requirement to ensure the deployed software has been installed. I created a Integration project that executes the sp_SWM_SoftwareComplianceStatus stored procedure.
My workflow adds computers to Filters to achieve deployment. In order to determine if the software has been installed the basic logic is:
For each request detail
Get the Filter guid
For each Policy associated with the Filter guid
Execute the Software Compliance Report
If all Policies associated with this Filter/computer combination are compliant
The software has been installed
Else
The software has not yet been installed.
I run this process every couple of hours to process all outstanding requests (waiting for confirmation). As details are found to be compliant, I change their status to complete. Once all details are complete the request is marked as complete.
See the attached package files.