[SPOILERS] Two things I noticed about the Perita Rebellion.

On average you'd be able to complete 8 orders. 6 if you're really unlucky (like getting the Conculyst Scout escort mission), 10 if you're really lucky (getting the Exterminate-like objectives multiple times in a row).

Also, I think the map is designed like it's 4 arenas connected by hallways in a single line.