I was getting ready to post a link to that post by VIOFO. 🙂
What I saw a lot when in the electronics world were a manufacturer would offer the same chip with the same, or slightly different features to a particular customer. This was usually driven by that customer wanting a special set of features or limitations. So a company to prevent confusion with other manufacturers thinking a certain chip had or did not have a set of features, they would gladly make a production run with whatever feature set but a different number. Component wise, it was exactly the same product, just that software wise there were slight differences, or perhaps how it would be mounted to the board.
Of course, sometimes there were no differences and the end customer just wanted a marketing advantage. But, who knows, a Novatek employee might have typed in the wrong characters when the chip went through etching process for identification. Turn out 15,000 like that and you don't trash them, you just add that number to the catalogue. 🙂