Attribute as a key figure calculation not working

Hi

I am trying to calculate a key figure which is a difference between two dates.

KF:

OTD1@REQUEST=AVG(OTD1@PERORDITEM)

OTD1@PERORDITEM=Date2-Date1.  Date2 and Date1 are attributes of the same master data type..

I am not able to get an output when I try to display OTD1 through the excel view.  OTD1 is defined as "attribute as a key figure" with The Time Reference Attribute being "Date1".

Any insight would be appreciated.

Thanks

Krishna