Create a dashboard in a folder named SPM Dashboard and with the unique name Attach_Rate, to see the View Dashboard link in SPM configuration screen for this metric.

Create summary reports with charts on SPM - Attach Rate object, to get the status of coverage of installed products by warranty / contract / both / none.

Grouping and aggregation can be done on any of the following attributes:

Covered By (Warranty, Contract, Warranty and Contract, Not Covered) is another attribute available OOTB for reporting.