Custom scan not detecting tracking cookies (which are detected by full system scan)

NIS 2010 "Idle Full System Scan"   detects persistent tracking cookies, for example  C:\Documents and Settings\Administrator\Cookies\administrator@atdmt[x]. But when I set up a custom scan on Folder C:\Documents and Settings\Administrator\Cookies or a custom file scan on C:\Documents and Settings\Administrator\Cookies\administrator\atdmt[x] NO THREAT IS DETECTED.

 

What's up with that?

 

I expect and desire that the Custom Scan should detect these tracking cookies. Have I set things up wrong or is this a proverbial "undocumented feature."