So, I put power leveling in quotes here because this is more of a way to cheese the game instead of actually doing the work of leveling your characters. It's still a good tactic to know in case you get stuck in the game. For reference, I'm close to half way through the game and have had no issues with difficulty while playing the game normally. This is kind of an overkill strategy, but I thought I'd bring it up anyway.
With that preamble out of the way:
In Type-0 after you play the first handful of missions you will unlock the arena. It's an area of the military academy that's blocked off for the first part of the game. Once you unlock it you get the ability to use one of the trainers their. He acts like a special save point. You initiate a conversation with him, while controlling whatever character you want to receive the special training, and he'll save your game and quit you out to the title screen. The next time you load that save game it will look at the amount of time that has passed and level your character up accordingly.
Do you see how to break this system? It boils down to this. Save your game in the arena, as stated above. Then close Type-0, go to your PS4 system settings, increase the year of your system clock, load your save file, and you'll get the maximum amount of leveling up your character can get in one "Special Training" session. Rinse and repeat as many times as you want.
Interesting. Might think about trying it. My biggest problem with type 0 is the fact that they give you 14 characters, and it sort of annoying to try to level up that many. Not to mention how alot of the character development were accustomed to in final fantasy is somewhat diminished in this game since it is dispersed throughout 14 characters. Currently am about 20 hours into the game.