I think you're right. I believe this was when Panavision was not yet thought of as a threat by Fox, and they hadn't clamped down. To be perfectly honest, I don't know if it was Fox that put the kabash on the credits, or Panavision. Doug
If you wanted the CinemaScope logo on your film, and in 1960 the CinemaScope name still carried weight, you were going to be using lenses from Fox. That meant the Bausch & Lomb lenses. By that time Panavision was a direct competitor to Fox's brand I don't believe you could use Panavision lenses...