selection problem

[nelsonm]

i am trying to select orders with less than 2% gp. when i use the
following query it is also bringing up orders with gp% greater than
..02, not all the orders with gp% greater then 0.02 only some. help.
thanks.

SELECT SO1_SOEntryHeader.SalesOrderNumber,
Max(SO1_SOEntryHeader.SalesOrderDate) AS MaxOfSalesOrderDate,
Max(SO1_SOEntryHeader.CustomerNumber) AS MaxOfCustomerNumber,
Max(SO1_SOEntryHeader.SalespersonCode) AS MaxOfSalespersonCode,
Sum(SO2_SOEntryDetailLine.Extension) AS SumOfExtension,
Sum([IM1_InventoryMasterfile]![StdCost]*[SO2_SOEntryDetailLine]![QtyOrdered]*[SO2_SOEntryDetailLine]![UMConvFactor])
AS COST, Max(SO1_SOEntryHeader.SalesOrderType) AS MaxOfSalesOrderType,
(Sum([SO2_SOEntryDetailLine]![Extension])-Sum([IM1_InventoryMasterfile]![StdCost]*[SO2_SOEntryDetailLine]![QtyOrdered]*[SO2_SOEntryDetailLine]![UMConvFactor]))/Sum([SO2_SOEntryDetailLine]![Extension])
AS gp
FROM IM1_InventoryMasterfile INNER JOIN (SO1_SOEntryHeader INNER JOIN
SO2_SOEntryDetailLine ON SO1_SOEntryHeader.SalesOrderNumber =
SO2_SOEntryDetailLine.SalesOrderNumber) ON
IM1_InventoryMasterfile.ItemNumber = SO2_SOEntryDetailLine.ItemNumber
GROUP BY SO1_SOEntryHeader.SalesOrderNumber
HAVING (((Max(SO1_SOEntryHeader.SalesOrderType))="S" Or
(Max(SO1_SOEntryHeader.SalesOrderType))="B") AND
(((Sum([SO2_SOEntryDetailLine]![Extension])-Sum([IM1_InventoryMasterfile]![StdCost]*[SO2_SOEntryDetailLine]![QtyOrdered]*[SO2_SOEntryDetailLine]![UMConvFactor]))/Sum([SO2_SOEntryDetailLine]![Extension]))<0.02));