Copying values between two matching values...

[p45cal]

For the original data in columns a try a macro:

Sub blah()
For Each are In Columns("A:A").SpecialCells(xlCellTypeBlanks).Areas
  If are.Row > 1 Then
    If are.Cells(1).Offset(-1).Value = are.Cells(are.Cells.Count).Offset(1).Value Then are.Value = are.Cells(1).Offset(-1).Value
  End If
Next are
End Sub