I wondered the same thing myself.
I drilled both balls the same and kept the cover prep identical (2000 w/polish).
As advertised and stated on these forums the Backdraft reads the midlane stronger and has more overall hook than all of the other QZ bowling balls.
The Backdraft is stronger overall not just b/c of the hybrid coverstock, but also the higher Ra values associated with the cover. What this means is that the cover has deeper/bigger peaks and valleys. This is how most high end balls create friction and hook. Those peaks gradually get smoothed out, and if the ball is not properly maintained you will see a decrease in a ball's reaction overtime. Sorry for the rant. Just trying to help.
For reference my QZ2 I used were drilled w/ a 4" pin to PAP above the fingers with a hole on my axis.
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