This scheme is known as "6 and 2", and was used on Apple Pascal, Apple DOS 3.3 and ProDOS, and later on the 400K and 800K 3½ disks on the Macintosh and Apple II.
This was made possible as the SuperDrive now utilitized the same MFM (Modified Frequency Modulation) encoding scheme used by the IBM PC, yet still retained backward compatibility with Apple's variable-speed zoned CAV scheme and Group Code Recording encoding format, so it could continue to read Macintosh MFS, HFS and Apple II ProDOS formats on 400/800 KB disks.