I also got the email yesterday about AP rates, but when I logged in they were the same old rates thru June 3. I don't understand why they sent the email unless rates are supposed to be extended but they're not showing up online.
As far as OP's question, I'll chime in with the others and say that normally AP rates are indeed offered most of the calendar year except for peak season times, though over the last couple of years they have included some peak times but I believe that is due to slow economy.