I agree with you. I think I have tome to that conclusion too. Thank you for the feedback. I appreciate it.If I were in the market for preloved Tiffany: I wouldn't consider any other written documentation the equivalent of the original Tiffany paperwork & documentation.
If I were familiar with the piece and felt comfortable enough to authenticate it myself & have an appraiser of MY choosing agree, then I would go ahead without the Tiffany paperwork.
If it were for insurance purposes: An appraisal by a qualified professional should be enough.
I'm not sure why else you would want this as you've repeated that you know it's authentic? In my opinion, no secondary paperwork is the absolute equivalent to actual original Tiffany paperwork.