Inthepresentarticle,wedealwiththeso-calledoverconvergencephenomenoninCofaslightlymodifiedPost-Widderoperatorofrealvariable,thatiswiththeextensionofitsapproximationpropertiesfromtherealaxisinthecomplexplane.Inthissense,errorestimatesinapproximationandaquantitativeVoronovskaya-typeasymptoticformulaareestablished.