This is discussed in another thread. Short answer, no one knows for sure. Rules just say make reserv. during the period and fly later -- BUT also says they will post bonuses 1 week after end of program.
My guess, if you book a flight now for next FEB, you will not get the bonus. Yet it seems odd one could book on last day and then SW expects you to fly that day (or within a week) to get the bonus.
Standard insufficient communication in Rules.