Timer offline laufen

[chiller4fun1990]

Hallo
Habe folgenden Code:

Delphi-Quellcode:

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, IniFiles, ExtCtrls, StdCtrls;

type
  TForm1 = class(TForm)       
    Button1: TButton;
    Label1: TLabel;
    Timer1: TTimer;
    procedure Button1Click(Sender: TObject);
    procedure Timer1Timer(Sender: TObject);
    procedure FormActivate(Sender: TObject);
      private                        
    Zielzeit: TDateTime;
    { Private declarations }
  public                        
    { Public declarations }
  end;

var            
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
var
  ini: TIniFile;
  filename: String;
begin
  filename := ExtractFilePath(ParamStr(0)) + 'einstellungen.ini';
  ini := TIniFile.Create(filename);


  Zielzeit := now + 1;  
  

  try
   
    ini.WriteDateTime('Daten','Zielzeit',Zielzeit);
      finally
      ini.Free; 
  end;


  
  Timer1.Enabled:=true;

end;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
  
  Label1.Caption:= TimeToStr(zielzeit - now); 


  
  if now >= Zielzeit then     
                
  begin
  Showmessage('Klappt');
  Timer1.enabled:=false;
  end;


end;

procedure TForm1.FormActivate(Sender: TObject);
var
  ini: TIniFile;
  filename: String;
begin
  filename := ExtractFilePath(ParamStr(0)) + 'einstellungen.ini';
  ini := TIniFile.Create(filename);

Zielzeit:=StrtoDateTime(ini.ReadString('Daten','Zielzeit',''));
end;


end.

Nur wieso stoppt der Countdown nach ablauf der Zeit nicht sondern fängt von neu an?
lg