Private Sub Workbook_SheetChange(ByVal Sh As Object, ByVal Target As Range)

'водим дату открытия и закрытия сессии
If Not Intersect(Range("J5:U" & Range("C4").End(xlDown).Row), Target) Is Nothing Then
Range("F" & Target.Row) = IIf(Range("E" & Target.Row) = "Д", Date, "")
End If

If Not Intersect(Range("G5:I" & Range("C4").End(xlDown).Row), Target) Is Nothing Then
Range("W" & Target.Row) = IIf(Range("V" & Target.Row) = "Сд", Date, "")
End If

'создаем примечание с датой сдачи экзамена
If Intersect(Target, Range("AG:AG")) Is Nothing Then Exit Sub

Dim oComment As Comment
On Error Resume Next
Set oComment = Target.Comment
If oComment Is Nothing Then
Target.AddComment Target.Text & " " & Range("AI" & Target.Row)

Else
oComment.Text oComment.Text & Chr(10) & Target.Text & " " & Range("AI" & Target.Row)
End If
End Sub