AS2005. Aggregate - Last Argument = Bug?

Hi,

some people say that the function aggregate() perfoms quicker without last argument. It's right.
But witout last argument it can returns wrong result. It is nasty :-(

For example

WITH
member [Date].[Calendar].[Column 0] as AGGREGATE({
[Date].[Calendar].[Month].&[2004]&[1],
[Date].[Calendar].[Month].&[2004]&[2],
[Date].[Calendar].[Month].&[2004]&[3],
[Date].[Calendar].[Month].&[2004]&[4],
[Date].[Calendar].[Month].&[2004]&[5],
[Date].[Calendar].[Month].&[2004]&,
[Date].[Calendar].[Month].&[2004]&[7],
[Date].[Calendar].[Month].&[2004]&}
)
--, Measures.CurrentMember)

SET [RowSet0] AS {[Customer].[Customer].[All Customers].children}
SET [RowSet1] AS topcount([RowSet0],100,([Date].[Calendar].[Column 0],[Measures].[Internet Sales Amount]))
SET [TotalSet] AS [RowSet1]

SELECT {[Date].[Calendar].[Column 0]} ON COLUMNS,
CROSSJOIN({[Customer].[Customer].[All Customers],[RowSet1]},{[Measures].[Internet Sales Amount], [Measures].[Internet Order Count]})
ON ROWS
FROM [Adventure Works]

I wonder... is this the same problem as I describe here:
http://cwebbbi.spaces.live.com/blog/cns!7B84B0F2C239489A!889.entry
? Looks very much like it. In which case it's a feature and not a bug, but I agree, it's a pretty confusing one and something that does need to be changed.

Chris