Untitled

Sub SummarizeColumns()
    Dim lastRow As Long
    lastRow = ActiveSheet.Cells(Rows.Count, "Q").End(xlUp).Row
    If Cells(1, "Q").Value = "VO" Then
        For i = 4 To lastRow
            Cells(i, "G").Value = Cells(i, "Q").Value + Cells(i, "S").Value
        Next i
    Else
        For i = 4 To lastRow
            Cells(i, "G").Value = Cells(i, "S").Value
        Next i
    End If
End Sub