SalesPickingList vs SalesPickingListJournal report

What is the difference between the SalesPickingList report and the SalesPickingListJournal report? When a picking list is posted for a sales order the SalesPickingListJournal report is run but when the original picking list is re-printed from the SalesTable form via Inquiries → Picking list which launches the Picking list journal form and then via Show ->Original the SalesPickingList report is run. Why are there two seperate reports here? Cheers Mark