The built-in Installed Software report shows the number of managed computers with the identified software installed. In this report both active and non-active (e.g. retired) computers are evaluated. Whereas, the drill-down report for this report lists the names of the active managed computers with the selected software; and excludes non-active computers.
Similarly the built-in Installed Software by Computer report and the Active Center also only list active managed computers, and exclude non-active computers.
Note: The attached reports and SQL Queries are provided as examples only. They are supplied as-is and are not guaranteed to be accurate or suitable for your purposes.