inventory aging - find difference

Hi guys,

I have 2 variables on fiscal year/period to get total stock and total value for inventory for different dates. I am getting the following result

06/2007----

05/2007

Total stock Total Value-Total Stock Total Value

05 10000 07 14000

My user wish to include one more column which gives me the difference between total stock and total value in a new heading.

06/2007--

Difference

Total stock Total Value-Total Stock Total Value-Total Stock Total Value

05 10000 07 14000 2 4000

I dont know how to get that. I can't use formula because there is only one key figure for total stock and total value. I would appreciate if someone can help me with that.