I've never seen this before, but here you can see the copyright and royalty information for all Sum 41 songs. I don't know how the site works but, I did hear that primary songwriters are listed in order...and for every song before Underclass Hero, Greig Nori is listed as the primary songwriter, with Deryck second. I'm not sure if that is how the site works but apparently Greig and Deryck co-wrote almost every song.ASCAP is a membership association of more than 350,000 U.S. composers, songwriters, lyricists, and music publishers of every kind of music. Through agreements with affiliated international societies, ASCAP also represents hundreds of thousands of music creators worldwide. ASCAP is the only U.S. performing rights organization created and controlled by composers, songwriters and music publishers, with a Board of Directors elected by and from the membership.
ASCAP protects the rights of its members by licensing and distributing royalties for the non-dramatic public performances of their copyrighted works. ASCAP's licensees encompass all who want to perform copyrighted music publicly. ASCAP makes giving and obtaining permission to perform music simple for both creators and users of music.
List of all Sum 41 songs (with some working titles)
Every song written or co-written by Deryck
And finally, every song by Greig Nori.
I'm not implying anything, but I thought that was an interesting find. Don't take my word for it, I doubt Deryck was secondhand in writing all of his own band's songs.