Proc CR is a procedure to facilitate cash recovery. Cash recovery from supplier overpayments is often possible regardless of how well the internal controls have been designed. Best practices and stringent controls can reduce duplicate invoice payments to less than half a percent. However, this error rate seems largely unaffected by automation. There are a variety of reasons why this is the case, e.g. multiple (non-integrated or non-communicating) systems, human error, intentional override, system failures, etc.