If you're using the IQ on the same oil/lane as the Tour, you may be finding it weak because there's not enough oil for it. The IQ is a stronger ball overall than the Tour, in that it requires more oil to perform. So, what could be happening is the IQ is using up most of its energy in the heads and the midlane, and it has none left to hook or to hit the pocket strongly.

To counter this you may need not a rough surface, but a smoother one or even polish.