differing a model by one digit and a minor feature is an old school game retailers started to run decades ago. back in the day when we had many big box electronics retailers who all price matched and beat a competitors price it could be real difficult getting that match/deal because on this minor difference.
Example, Receiver A and Receiver B are from the same manufacturer, have the same model name, but since their UPC code is different they don't price compete per small print the big box stores employed. It may even be useful to keep current online comparison systems from doing the same. To truly make the receivers different they usually swapped which extra port they featured on the back even though the guts of them were identical