I am attempting run the following MDX query to determine the distinct amount of transaction numbers for a set including 2 dimension attributes. (POS and Concierge) When I run the query, I seem to be getting the distinct amounts for each added to together. If the same transaction number exists in both, they are both counted. However if I attempt to get the same result using an Excel Pivot table, I get the desired transaction number count. Could anyone help me with getting this result in the MDX query?

Code:
WITH

SET [Week]	AS StrToMember("[Date].[Hierarchy - Fiscal].[Fiscal Week].&[2012]&[48]")

SET [Store]	AS {[Financial Transaction Channel].[Transaction Channel Desc].&[POS],
			[Financial Transaction Channel].[Transaction Channel Desc].&[CONCIERGE]}


												
MEMBER [Store Transactions With Returns] AS 	SUM([Week] * [Store], [Measures].[Operational Transactions Count])


SELECT
{
	[Store Transactions With Returns]
} ON COLUMNS,
{
	[Week]
} ON ROWS
FROM EDW

Results: 		Store Transactions With Returns
Wk. 48 - 2012 			78,636
The same attempt using an Excel Pivot table yields this:

Code:
Row Labels	Operational Transactions Count	
Year 2012	          78,368	
  Half 2 - 2012	          78,368	
    Qtr. 4 - 2012	  78,368	
      December - 2012     78,368	
        Wk. 48 - 2012     78,368 78,636
          1 US STORES     78,368	
             CONCIERGE     3,668	
             POS          74,968	
Grand Total	          78,368
If you add the POS and Concierge amounts, you get 78,636. Which is the same result I am getting from my MDX query, but after I went through the transactions line by line, I was able to determine that 78,368 is the correct amount of distinct transaction numbers.


Any help on this would be greatly appreciated.