<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by Radiocycle:
There is a way you can (probably) still snag one of the P5 seats.</font>
Online check-in does not allow one to grab a P class seat for an upgrade from a discounted fare.
Online check-in does place one on the waitlist for an
F class seat when it opens up just prior to departure.
There's a big difference as P class gives a 50% bonus while F class does not.