This single has at one hand a bit a confusing tracklist, and on the other hand it is logical. This single contains the tracks Superman, and those are taken from the album "Holdin' On". This album seems like a (sort of) special version of the album "I Wish", only the album is titled "Holdin' On" and has more tracks, while the tracklist is the same as "I Wish", till track 12..
Confusing:
At the release linked below this is true:
There Supermix 2 is the album version... That version has the lowered echo at 1:40-1:43. It is found on the regular album "I Wish".
http://www.discogs.com/release/1963876.
On this release it is vice versa.
It seems that the album "Holdin' On" uses the mix version without the lowered echo, here called Album Cut. The Supermix is here (and on the album Holdin' On) in fact a shortened version of the version on the regular album "I Wish". At the single above mentioned here in notes, also known as Supermix 2.