During the last year or three of the company's existence Louis-Benjamin Audemars-Valette (my great Grandfather and the grandson of the original L-B A) "bought" (probably using his wife's money - she wasn't short of a franc or two) large numbers of finished and unfinished movements as well as some finished watches. There is some evidence from my archive that he did so at "knock-down" prices.
His original idea was to finish them at his own expense so they could be sold to restore the company's fortunes but, as it became clear that wasn't going to work, he stockpiled them and used them to found his own successor business also - and confusingly - titled "Louis Audemars & Cie".
He certainly signed his watches as such as well as selling (as you have noticed) watches to some of the original company's customers.
Watches by his company are now - in my opinion - very rare indeed as it didn't last very long.
(We have no archive or records from hs successor company).
If made by him using a movement from the original company (especially if its number appears in my ledgers) they can usually be identified by a disparity between the movement number and the case number as he certainly bought his cases in - and very probably not from Meylan Freres (as did the original company) because they would have been owed a lot of money and the Audemars family were less than totally popular in the village for a while after the bankruptcy.
It has been suggested by people more knowledgeable than me that the case quality of his watches is not as good as those used by the original company.
If the movement serial number in a "Louis Audemars" watch has six or more digits it is almost certainly made by him after the bankruptcy and not one of the ones he had acquired. ( I have a small "Louis Audemars" ladies watch with a six-digit serial number bought recently on e-bay , which is one of his)
The vast majority of movements & watches from the original company had 5-digit numbers; some four- and even three-. The only 6-digit numbers appearing in my archive are - as far as I can tell - movements "resourced" from other producers (Courvoisier, Calame-Robert) and sent (directly?) to Audemars London depot in the final years of the company, where they were finished and - very probably - sold with the retail customers' signatures.
There were two other successor companies also started by grandsons of the founder - Audemars Feres and Francois Audemars fils. I have no indications that Audemars Freres were using materiel from the original company but it would not surprise me. I have records of a very few movements acquired by Francois Audemars.
There was a fourth "successor" company Louis Audemars & Co Ltd. started by my grandfather some time after he emigrated to London between 1885 and 1900. He certainly processed a few movements from the original company. It would not surprise me in the least if he signed them "Louis Audemars & Cie" but I have no evidence of that.
(His main business was importing watches and/or movements and selling them to retailers either with the customers' signatures or his own - by the way if anyone out there has a ladies wristwatch with "Audemars" on the dial, I will be very interested).
Some very complicated movements from the original Ls Audemars company were in the safe at 66 Hatton Garden when the building was destroyed in the 1940's blitz on London. The contents of the safe were recovered but the movements were like burnt chestnuts and unrecoverable. I played with them as a child.
The same raid destroyed all the medals and certificates awarded to the original Ls Audemars & Cie together with a number of seriously important watches which were displayed there.
Another reason for attributing a watch to a date after 1885 is that some of the Auction Houses assessors don't know the history and are dating it solely on its appearance and attributes. There was such a case very recently in a german catalogue. Such judgements are perforce subjective and errors of +/- five or more years are forgivable - especially as some of the more complicated watches were several years in the making.
Finally, there are somethimes "Louis Audemars" wristwatches available on-line claiming to use original movements.
They come from Kiev so they must be right.
Hope this is some help.
I am at your disposal for any more information you or others may require.
PS We have copies of a handwritten account (in French) of the rise and fall of the original company written in 1922 by Louis-Benjamin Audemars-Valette from which a lot of Herr Zantke's account was derived.