private string FormatRoundtrip (double origval, NumberFormatInfo nfi) { NumberFormatter nfc = GetClone (); if (origval >= MinRoundtripVal && origval <= MaxRoundtripVal) { string shortRep = FormatGeneral (_defPrecision, nfi); if (origval == Double.Parse (shortRep, nfi)) return shortRep; } return nfc.FormatGeneral (_defPrecision + 2, nfi); }