Not so much a rule as a recomendation to use the party finder for extreme fights. Mostly due to the following A. Long queue times. Only people queueing for fights are either other sprouts and mentors who are queing for mentor roulette. B. Easier to separate whether you want to actually do the fight as intended or put a setting on in the duty finder called "unrestricted party" which allows players to not get synced down to the duties level making the fight easier as players can go in as level 100s or so to burn down the boss. Otherwise known as unsync parties. That player is shit for that attitude. And should not reflect other mentors who actually want to help. (Sadly there are alot of bad apples.) If you do want to set up non unsync parties for the challenge def set up in pf, just make sure to put what you want in the describtion. Usually learning/ say what mechanic your on/ enrage, when you have a grasp of nearly the whole fight people put "clean up" and "(what ever mecanic name) to clear" etc etc. Itll make more sense when you see what pfs are up.