Dave, I have a question about the older DX as opposed to the newer DX....

Is there any way the older DX plastic made discs more stable. For instance, I have ALOT of older DX Rocs and threw a NEW one yesterday and it was VERY stable, as most of my older Rocs are. Now, I also have a Ring of Rocs stamped DX Roc and it is NOWHERE near as stable new compared to the older DX. They are both Ranchos so they are the same mold... Thanks in advance.

Also, if the plastic is different, why the change?