I don't think deferred rush/recruitment is such a hot idea. My alma mater is going to deferred rush (February) for the first time this year, and I'm afraid that numbers are going to drop dramatically, and that my chapter, already much smaller than the others on campus, might close.
The fraternities at my school are also going to a slightly-deferred rush - September instead of August - and the administration has as much as said that they expect some of the smaller fraternities to close as a result.
With deferred rush, PNMs have spent at least one semester in school (and started to feel the associated pressure), made some friends, perhaps gotten involved in some clubs/sports/activities and/or gotten a job, and they may feel (rightly or wrongly) that they don't have time to devote to a sorority - so they don't even come out for rush, whereas they might have if rush weren't deferred.
Another argument for non-deferred rush is that new members will have the support of their sisters as they make the transition from high school to college. It's not an easy transition, and I can't begin to tell you how supportive my sisters were of me during my first semester.