This feature extends the sales tax calculation functionality for return order and credit note. For a return order/credit note, the actual sales tax of the returned item should be the same as the original sales tax which is charged on the sales invoice. Enable this feature to bring forward the original sales tax transactions from the sales invoice to the return order/credit note as tax adjustments to ensure the same amount be returned. Please notice that to edit the return order or credit note line that brings the tax adjustment from the original sales order, the feature "Allow the editing of the sales tax adjustment when modifying lines in the return order or credit note" has to be enabled.