I got 45 days too. I didn't know what the reasons were though. I thought it had to do with veteran rewards as when I logged in I remembered getting 4 and 5 years rewards, but that's something in-game I guess. Sounds like the 30 days + 15 day hacking compensation that others are talking about.
I started two accounts by accident: one in 2003 and the other in 2006. I'm on my 2006 account, and I can't get into my old one. I just asked Sony to see if they could merge them, so I'm interested to see if there is more free time too