Georgia, just heard from my sister in law and she keeps her stone in the oven all the time. She preheats the oven w/the stone in it @ 475. She said she gets the crispiest crust that way. I've always done 450 but now I'll increase it.
It could be your oven. Try preheating it with the stone and check the time with and w/o the stone. Good luck! Hope this helps!
<img src="http://www.traveltalkonline.com/forums/images/graemlins/handshake.gif" alt="" /> Contessa
