Sub ZZZ()
    Row = 2
    Do While Cells(Row, 1) <> ""
        If Cells(Row, 10) = "Месяц май" Then
            Rows(Row + 1).Insert
            Rows(Row).Copy Destination:=Rows(Row + 1)
            Cells(Row + 1, 11) = "Дубль"
            Row = Row + 1
        End If
    Row = Row + 1
    Loop
End Sub

Sub mrshkei()
Dim lr As Long, i As Long
lr = Cells(Rows.Count, 1).End(xlUp).Row
For i = lr To 3 Step -1
    If Not IsEmpty(Cells(i, 10)) Then
        Rows(i).Insert
        Rows(i + 1).Copy Destination:=Rows(i)
        Cells(i, 10).Copy Destination:=Cells(i + 1, 11): Cells(i + 1, 11) = "Дубль"
        Cells(i, 3).FormulaLocal = "=" & Cells(i, 3).Value & "-" & Cells(i + 1, 3).Address
    End If
Next i
End Sub