Public Function RowOutlineLevel() As Byte
   Application.Volatile
   
   Dim rCallerCell As Range: Set rCallerCell = Application.Caller
   
   RowOutlineLevel = rCallerCell.Rows.OutlineLevel
   
   If RowOutlineLevel = 1 Then
      Dim wsh As Worksheet
      Set wsh = rCallerCell.Worksheet
      
      Dim bSummaryRowIsAbove As Boolean
      bSummaryRowIsAbove = wsh.Outline.SummaryRow = xlSummaryAbove
      
      Dim lCallerCellRow As Long: lCallerCellRow = rCallerCell.Row
      
      If bSummaryRowIsAbove And lCallerCellRow = wsh.Rows.Count _
           Or Not bSummaryRowIsAbove And lCallerCellRow = 1 Then
         RowOutlineLevel = 0
         Exit Function
      End If
      
      Dim bNextCellRowOutlineLevel As Byte
      bNextCellRowOutlineLevel = rCallerCell.Rows(-2 * bSummaryRowIsAbove).OutlineLevel
      
      RowOutlineLevel = 1 + (bNextCellRowOutlineLevel = 1)
   End If
End Function

= RowOutlineLevel()