The costs of manual three-way matching involve more than actual dollars. For the AP department, there's real stress in having to chase down details generated by poor or misplaced documentation, as well as having to tackle a tall pile of invoices that grows bigger by the day. Human error is another 'gotcha'. It's not hard to imagine the foibles of human error cropping up among the dozens of small details that need to be tracked. Not only does that create more work for the AP team, but they might need to drag the warehouse and procurement managers into the resolution.