A live order does not fail at the carrier cut-off. It fails earlier, when a picker reaches a location the system said was full and finds it empty, or finds the wrong SKU. By then the wave is already late, and the recovery is a manual exception. In most buildings nothing tells the operator that ahead of time. The warehouse management system shows an expected on-hand quantity and a location. Both are claims until a person verifies them. The cost of that gap is already measured