Our Collegiate Panhellenic designates a week in which the Associate/Local chapters are allowed to recruit, and we can COB after that. The week is always after formal recruitment for the NPC chapters. One benefit of this is that any girls who may have been cut from NPC recruitment still have options.
Also, our 6 NPC sororities on campus only have fall recruitment, whereas the Associates & Local (and OPhiA too--which doesn't affiliate with CPC on our campus) also have spring recruitment. That helps.