The miscellaneous charges are in the transaction details in the same table as all line items, including regular items, miscellaneous charges, comments, and instructions. Each line is has a line type that allows you to segregate the lines, and the miscellaneous charge code is in the same field as the item #.
The transaction table includes PO's, Receipts, and Invoices(Adjustments). If your freight costs are booked when you enter the receipt then filter out transaction type "2" as a receipt, or type "4" if you are booking freight details only as an Invoice.
Best,
Brian