As far as I know, Funimation has never done any work with Bang Zoom. The unofficial rumor is that there's bad blood between them and Eric Sherman. All of the Los Angeles dubs that Funi has had done were recorded at either New Generation Pictures (Hellsing: Ultimate, Bayonetta, Ikki Tousen), Studiopolis (Afro Samurai), Redshift Productions (Tenchi Muyo GXP), Patrick Seitz's Cup of Tea Productions (BlazBlue Alter Memory), or Todd Haberkorn's own personal studio, which is where Yuki-chan was done.
Afro Samurai's dub was made before Funi licensed it, andAlter Memory was done at Cup of Tea because that's where the games are done (and does Seitz own that studio).
Concerning NGP, the only reason Funi ever has business relationships with that studio was because they used their talent in their dubs (i.e. Patrick Seitz, Taliesin Jaffe, Carrie Savage, Christopher Corey Smith, etc). And I dont think there's some bad blood between the two companies. It's just that Funi has never used that studio ever.
Also, Haberkorn has his own studio?