Different Result between Pivot and Non-Pivot Queries

I have two queries, one is a pivot query and the other is the same query but does not perform the pivot.  The pivot query provides the data table for a report and the non pivot query provides the data for a graph. In the pivot query the aggregate function is performed in the pivot section and in the non pivot query the aggregate function is performed in the select statement.  My problem is that the result does not match in one column between the two queries.  Can anyone tell my why?  If I change the pivot query to perform