Second time guys have a much higher percentage of success. The PIC requirment was changed due to the lowering number of military folks that are able to achieve the 1300 PIC requirment once they get out. The percentage of folks being hired is about 60 percent civilian and 40 percent military. SWA tries to keep this about 50/50. Some guys are getting out without the requirements and have no way besides working at regionals or other outfits for years before getting more PIC requirments. Hence, why it was lowered.
Also, in your second try, you only compete against those that previously interviewed when determining who get's a second shot at an interview. You don't compete against those still waiting for the first try.