Per the Wayback machine, that page was first found and archived at the beginning of 2015:
https://web.archive.org/web/*/https://support.apple.com/en-us/ht204310
That page has a "last modified" date of Feb 19, 2015. In theory it could have been posted before that, and just it took a while for the Wayback to find it. These are indirect indicators, of course.
Also, not certain if there is a loss of quality in going from the Apple standard to MP3 but that is okay since most of the devices that we play the songs on are not the best acoustically.