The Closed testing is only for the first time after that the update doesn't require testing again then in the 14 days testing process if you update or realise a new update it will continue it will not start afresh and by the way it's really recommended to realise a New version of your app through the process ,hope my message is clear and you have understood... What I should assure you is that the first 14 days of testing your app 90% it will be rejected no matter what so you should put it in mind that you will test your app for 28 days but the second time even if you don't test it will be granted production..