How inc ddd hh:mm:ss into my datetime?

Hello guys

I have a maskedit where I inform ddd hh:mm:ss and I want to inc my date, I tried this code and it works fine for days but not
for hours :(

For example:  001  02:35:40 add to my date 07/11/2017 13:00:00

procedure TFDatasPrevisao.MaskEdit1Exit(Sender: TObject);
var
  dias, horas, minutos, segundos : String;
  Dt   : TDateTime;
begin
  Dt       := MaskEdit1.DateTime;
  Dias     := Copy(MaskEdit3.text, 1,3);
  Horas    := Copy(MaskEdit3.text, 5, 2);
  Minutos  := Copy(MaskEdit3.text, 8, 2);
  segundos := Copy(MaskEdit3.text, 11, 2);

  if StrToInt( dias ) > 0 then
  Begin
    dt := IncDay(dt, StrToInt( dias ))
  End;

  if StrToInt( horas ) > 0 then begin
     dt := IncHour(dt, StrToInt( horas ))
  end;

  if StrToInt( minutos ) > 0 then begin
     dt := IncMinute(dt, StrToInt( minutos ));
  end;

  MaskEdit2.Date :=  dt;

end;

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Whats is wrong? any clue for a better way?

thanks
Alexandre