Since pokemon.com has now said:
That seems to indicate that the tally for 2011-2012 Play Points will end after Nationals, which eliminates (for this year only) the situation of World's attendees having a huge jump in the PP Player-of-the-Year competition.The 2013 season will be starting on July 9th so that players can get an early start on working towards the 2013 Pokémon World Championships, but in order to avoid confusion we will rotate sets on the more familiar date of September 1st.