The　malfunction　of　measuring　apparatus　is　almost　inevitable　in　electric　system　and　will　result　in　inaccurate　settlement　amount　of　electricity　sales.　The　backup　measures,　such　as　dual-apparatus,　calculations　from　the　measurement　on　other　side　of　line　or　Tele　Meter　Reading　of　EMS　are　helpful　to　rectify　the　erroneous　data.　Data　interpolation　is　the　final　solution　as　those　alternatives　absent.　The　impact　of　estimation　of　measuring　data　on　settlement　is　different　while　the　period　of　electricity　prices　and　settlement　are　alternating　respectively.　©　2011　IEEE.