My A8 has been okay. It was manufactured in Feb. 2016 AFTER they changed the check ball (which resolved the transmission surge issue). So, I would add A8 manufactured Feb. 2016 or after to your list.
Check this link:I was gonna say the same thing. The TSB said fluid and the check ball issue mentioned earlier was for the A6, not A8. As always, verify what is posted here as sometimes inadvertent mix ups occur.