Originally Posted by STOMACHofSTEEL
Although it probably doesn't matter anymore, I somehow feel the need to give an answer. The "Max" Option became available to me later, after clearing "Dong Zhou in Luo Yang" or "Divided Land". I think you just have to play through a few scenarios.
I can confirm this. Can't remember exactly which scenario it was, but I believe the MAX officers option unlocked for me after completing 2 or 3 of them (always on the easiest difficulty, FWIW). Also, I'm not sure if it depends on the number of officers you've collected, but I had around 150 officers at that point.