That's rarefied air you're breathing there. Congratulations!
I'm sure that people smarter than me will be along to answer your question, but my own personal philosophy with this is, as long as I'm still stacking up the freeloads, and as long as I don't have a specific need for those additional days during the rest of my Select period, why not leave it free? If you can pick up another four or thousand free downloads, that will only help your positioning on the Pop lists going forward.
Unless something has changed recently and I'm not aware of it, which is entirely possible, and I recant everything I said.
Except "Congratulations!." That part I meant with no reservation.