Most likely (and correct me if I'm wrong!) what you heard is referring to total membership in each chapter, and eligibility to do COB after formal recruitment has finished.
It wouldn't surprise me if most or all of the sororities at Florida are over campus total after recruitment. What that means is that quota might be 60 but campus total is 150--
these numbers are examples only, I don't know the chapter sizes at UF 
Using this example, each chapter can take up to 60 new members during formal recruitment, even if it puts their chapter membership total over 150 women. If most chapters started with member totals of 90 or more, and they all get quota, then they'd all be at or over 150 women. That means they couldn't take any more members and not allowed to COB. The higher the number of returning members and new members, the less likely a chapter would be eligible to COB at any point during the school year.
Like KappaKittyCat said, if the chapter is still under campus total after recruitment then they would be allowed to have COB until they reached campus total. If all the chapters are at or over the campus total, then no one could extend bids until either are under campus total or the next formal recruitment period.
Hope this helps!
Christin