Okay, so I confronted our Greek Life Advisor and told her about the handbook, including the page number, etc. and she said that our school has had a summer disaffiliation regulation locally. I then asked her to see the regulation in writing, just because I want to clearly understand what makes our school so special that we can't follow the NPC rules, and she told me that it is not in writing; it is just a "verbal agreement" among sororities on campus.
I called my sorority chapter advisor and she's going to have a meeting with her and she has also called our local NPC rep. I'm not trying to cause problems--just understand our local rules and question why we have let this go on for so long if it is against the rules!