I found this while browing at work today. seems conflicting to me

S3B Standby Code
  • ExpressJet (formerly ASA) parents
  • ExpressJet (formerly ASA) retirees


S4 Standby Code
  • Buddy Pass riders
  • Parents and retirees of Compass, ExpressJet (formerly ASA), Pinnacle, Shuttle America and SkyWest