Expiration is extremely complicated, and there's different behaviours for different settings of Expiration Types, and how you've configured the policies in TSM.
Essentially, you'll never use -i, because you'll never archive IBM CMOD tables. Using -d will expire the metadata in the tables, and -c will clear data out of the cache. Depending on the Expiration Type that's set for the Application Group, IBM CMOD might tell TSM to remove some objects, or it might just leave TSM to do it's own expiration.
-JD.