I am using DVD maestro and have a film with 7 (yes count 'em) 7 audio tracks.

Seven???

I thought that you had settled for a meagre six audio tracks

1. AC3 1.0 Mono Track (1977 35mm Academy Mono track by Moth3r)
2. AC3 2.0 Stereo Track (1977 35mm Two track Dolby Stereo Track by Neil S Bulk)
3. PCM 2.0 Stereo Track (1993 Definitive Collection Two Track Dolby Stereo)
4. AC3 5.1 Surround Track (see note)
5. AC3 2.0 Stereo Track (Isolated Score Track created by Editdroid)
6. AC3 2.0 Stereo Track (Commentary Track from 2004 DVD Release)

* Track 4 is created from 3 separate sources.
a. 1993 Definitive Collection audio separated out into a 5.1 track using Adobe Audition (my own work)
b. 1997 Special Eedition 5.1 AC3 file created by Neil S Bulk, provided by Rikter and Russs15
c. 2004 official DVD 5.1 AC3 file.

I guess that the extra is track either the Definitive Collection LaserDisc commentary, the 1986 Digital Sound mix or Isomix isolated score......