Untitled

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