The delta of the ice on stone speed between the sides is not dependent on the rotational speed but liner speed in relation to the rotational speed.

You're wrong, and even if you were right that wouldn't argue against GP's observation.

V_cm: velocity of center of mass

V_l: velocity at left edge

V_r: velocity at right edge

R: radius of stone

w: angular speed of stone (CCW is +)

  V_l = V_cm + R*w
  V_r = V_cm - R*w
  delta = 2*R*w

Even if it was dependent on linear speed / rotational speed, the only way to change # of turns / run is to change linear speed / rotational speed.