If they are unblocking PC middle seats after 5/31, that is somewhat odd that flights in August would show up as blocked if they're not planning to extend the seat blocking in PC. Although it's making it far more difficult to upgrade to PC at T-72, my guess is that PC sales have increased with this policy so I wouldn't be surprised if they extended it although it's 5/28 so it seems a bit last minute if they did. An upgrade to PC if I didn't clear into F was almost a 100% guarantee in the past, but now that's not the case.