You cannot. 10-15 is only PVB points. And there are also some stipulations on that… see below…
I asked this question and was told specifically that developer inventory would only be used for NEW points and that you could not combine existing unused points and new points.
For example - if you bought 150 new points but had 100 from a previous PVB contract (either direct or resale) you could still only use 150 to book developer inventory - you could NOT combine and book a stay costing 250 points.
All PVB owners will be able to book between 10/15-10/30 but only NEW points (important to not the distinction is the points not new owners) will be able to ask for developer inventory.
See the above for an explanation of what my guide (who I know from previous recommend your guide threads is also YOUR guide

) explained today about this issue.
Important distinction - it was explained to me as NEW POINTS not new purchasers. New purchasers would automatically qualify (since their points are also new) but existing owners can also book from developer inventory too.
Ok this was my MOST IMPORTANT takeaway from my guide conversation today - CS will be able to convert existing tower cash reservations into points bookings starting on 10/15.
I’m going to restate that to be sure it’s clear: anyone who has an existing cash reservation for a tower room will be able to switch it over from a cash reservation to a points reservation by calling member services starting on 10/15. That option will be available ONLY until the existing PVB owner booking period for the tower is done through 10/30. Once the tower opens for all points/7 month window bookings that will no longer be possible.
All that leads me to believe that DVD held back a bunch of the cash inventory from the tower cash booking period (probably because they didn’t have their acts together/weren’t sure on points chart/weren’t sure on opening dates) and now are going to fill these “new point” bookings with those reserved cash bookings.
My guide said they did a pretty brisk business today and email docs would not go out until tomorrow for a lot of today’s purchases. I wouldn’t worry yet. If Thursday comes around and you still don’t have docs then send your guide a follow up.
We decided to go ahead with the 150 direct Poly points today

Thanks to everyone here offering advice and guidance. I’m still looking to add on again with resale once contracts come back down but I’m happy with my new blue card.