"Delete Package from client computer" behavior with Quick Delivery Tasks

I understand how postedExpiry works in package delivery and software management policies.  But I'm unclear of the expected behavior for quick delivery tasks.

In my quick delivery tasks, regardless of how they are configured 

-Unchecked 'if unused for"

-checked "if unsed for 0 days"

The setting is always "false" for postedExpiry.  So the cache files remain in the software delivery folders and never seem to delete.  Does package expiration not work with quick delivery tasks?  We are on SMP 7.1 SP1.

http://www.symantec.com/business/support/index?page=content&id=HOWTO9839