since they only start this in March 1st, so I would think this one will last until end of Feb.
Exactly. Since you're not requalified yet, the system reads your SE status as ending at the end of February. Since your flight is after that date, it only sees you as a lower status elite, thus not eligible for the reduction. Once your flights from this week post, and the sweep is done sometime next week, you'll not be able to book as an SE for any flights from March 1st onward.