Te anexo la macro actualizada:
Sub Insertar_filas2()
'Por.Dante Amor
Dim f, c, letra
Application.EnableEvents = False
Application.ScreenUpdating = False
f = Cells(Rows.Count, "L").End(xlUp).Row
vRows = Application.InputBox("Introduce el nº de filas a insertar", "Insertar Filas")
If vRows = False Then Exit Sub
Rows(f & ":" & f + vRows - 1).Insert Shift:=xlDown, CopyOrigin:=xlFormatFromLeftOrAbove
For c = Columns("L").Column To Columns("AK").Column
letra = Evaluate("=SUBSTITUTE(ADDRESS(1," & c & ",4),""1"","""")")
Cells(f + vRows, c) = "=SUM(" & letra & "8:" & letra & f + vRows - 1 & ")"
Next
'
For c = Columns("AM").Column To Columns("AO").Column
letra = Evaluate("=SUBSTITUTE(ADDRESS(1," & c & ",4),""1"","""")")
Cells(f + vRows, c) = "=SUM(" & letra & "8:" & letra & f + vRows - 1 & ")"
Next
[A9].Copy Range(Cells(f, "A"), Cells(f + vRows - 1, "A"))
[AR9].Copy Range(Cells(f, "AR"), Cells(f + vRows - 1, "AR"))
Rows(f - 1).Copy
Rows(f & ":" & f + vRows - 1).PasteSpecial xlFormats
[C3].Select
Application.ScreenUpdating = True
Application.CutCopyMode = False
Application.EnableEvents = True
End Sub