Drill through from AS to RS

[cognos2009]

Hello, I opened my cube in Analysis Studio. When I highlight Year Column Header (in my case 2007), Click on related link, click on 'View passed source value: it shows 20070101-20071231
Click on available link, view target mapping, it shows Display Value: 2007. Use Value : 2007-01-01

But when I highlight a cell of 2007 , Click on related link, click on 'View passed source value: it shows 20070101-20071231
Click on available link, view target mapping, it shows Display Value: 2007. Use Value : ("2007-01-01","2007-12-31")

Can anyone explain Why it is passing two different format for use value? 2007-01-01   vs  ("2007-01-01","2007-12-31"). I am supposed to get same USE VALUE for both situation. Not sure why highlighting column header vs highlighting cell is passing different value? Thanks for your help.

[AussiePete2011]

http://publib.boulder.ibm.com/infocenter/c8bi/v8r4m0/index.jsp?topic=/com.ibm.swg.im.cognos.ug_cra.8.4.0.doc/ug_cra_id37191UnexpectedResultsDrillingCubetoRelational.html