I believe this is a misconception, just because we used to have the same mis-understanding with staff where I worked. The misconception comes from being given

I believe this is a misconception, just because we used to have the same mis-understanding with staff where I worked. The misconception comes from being given a target-time which is based on a calculation assuming the task can be completed successfully with no delays, however afterwards the target-times are recalculated to account for the additional movement. A common assumption is that performance is (Time it took / Initial target time) - especially because the users see the target time - however it is really (Time it took / Recalculated target time accounting for additional movements). I'm not aware of Amazon's exact implementation - but all performance management suites I'm aware of will re-calculate afterwards based on 'actual' task rather than 'forecast' task.