Auto Fill not working

In the attached workbook I have code that I want to auto fill in Column C to the last populated cell in Column B.
I have done the same thing in Column B which works fine, but then when I play the code, the Column C doesn't auto fill.
What am I missing/doing wrong?

 Columns("C:C").Select
    Selection.Insert Shift:=xlToRight, CopyOrigin:=xlFormatFromLeftOrAbove
    Range("C1").Select
    ActiveCell.FormulaR1C1 = "WS"
    Range("B2").Select
    ActiveCell.FormulaR1C1 = _
        "=IF(AND(RC[-1]=R[-1]C[-1],RC[3]=R[-1]C[3]),R[-1]C+1,1)"
    Range("B2").Select
  Selection.AutoFill Destination:=Range("B2:B" & Range("B" & Rows.Count).End(xlUp).Row)
    Range(Selection, Selection.End(xlDown)).Select
    Range("C2").Select
    ActiveCell.FormulaR1C1 = "=IF(RC[-1]>R[1]C[-1],""L"","""")"
    Range("C2").Select
    Selection.AutoFill Destination:=Range("C2:C" & Range("C" & Rows.Count).End(xlUp).Row)
    Range(Selection, Selection.End(xlDown)).Select
 Columns("B:C").Select