They are really sticking to the target dates, so if your dates are not within these dates you are out of luck. You would have to be checking in by March 7th in order to get the code discount (pin).
target dates:
Feb 25 - Mar 7
nothing for most of March & all of April and most of May
May 28 - Jun 3
There are some AP discounts for March. Isn't there a package that offers the free hoppers to your tickets?
I tried to book a package today and I have pin codes, but my dates were not in the target range for August. I wanted to arrive 7 days before the target date of August 21, so the code would not change my rate. I can not change my dates. So will be watching for the next round of promotions.