Shipping Modifier

Client has a modifier for shipping charge which gets applied on both outbound shipment and returns.

If user enter Sales order,Charge is calculated;
(Order Qty X Unit Price) X Charge Rate, For ex:  Quantity is 40, Unit Price is 17.95 and Charge Rate is 0.17, So shipping charge is  (40 X 17.95) = 718, 718 X 0.17 = 122.06
Then system will store 122.06 / 40 = 3.0515 to ADJUSTED_AMOUNT_PER_PQTY on OE_PRICE_ADJUSTMENTS table with 3.05 not 3.0515

If user enter RMA, Charge is calculated as;
ADJUSTED_AMOUNT_PER_PQTY X RMA QTY, 3.05 X -40 = -122.00

So, there is difference of .06. Is there any functionality to handle this discrepancy?