I think Vauen probably makes their own stuff as well as pipe cleaners. The smaller brands of filters are likely made by Vauen and Kopp. White elephant are kopp. I think Molina 9mm are also kopp. Its a whole lot easier to have someone with the machinery make and label it for you.
Perhaps the specificatons on how much AC is in each is is different. Vauen also might not share their specific formula for AC with others and just do runs of filters with more generic AC. When you have machinery it is important, as a business, to keep it in use and bringing in cash. If nothing else you dont what that employee or employees sitting around with their hands in their pocket.