Problem using TIBDataSet and cacheupdate

I'm starting with IBX Update 4...

I've defined a TIBDataSet with Cacheupdates = True,
and I'm wondering why when I call the CancelUpdates method it only
cancels the first record inserted.

When I do 5 times : ( i=5)
 For i:=1 to n do begin
   Que_Author.Insert;
   Que_Author.FieldByName('ATH_NAME').AsString := 'Auteur n'+IntToStr(i);
   Que_Author.Post;
 end;
When I call Que_Author.CancelUpdates it deletes only the first record in the
cache.
( Of course no record is sent in the server ).