First, I would like to say that by no means am I saying anything negative about Scarab Arms or, even the individuals behind it.
I'm not just making speculations due to their lack of reply, nor am I saying that Perfect Circle is doing all of the development work. Scarab Arms could say they are involved in the development just by having Perfect Circle build them different projectiles to Scarab's specs for testing and final selection (i.e. "give us the fun pattern of the FN303 but, make the whole projectile a container, and give us fragmentation grooves in the nose sectin and fill from the rear").
Here's two other reasons for my speculation which I freely admit to be the case:
The similarity between the FS rounds, and Scarabs prototypes in the pics (fin height, angle, length, the interface between the nose section and the tail section- a "shoe box" joint used by perfect circle). What are the chances that these design features are not covered by patent/s?
Also, how many paintball companies (especially startups) have the capital available for developing a fin stabilized round of their own from scratch (i.e. optimal twist rate, length of skirt, center of gravity/pressure, etc, etc)? This doesn't even cover the material sciences knowledge pertaining to the shell material (i.e. something that breaks on impact but, not in the gun).