This variation occurs in the second bar of the first part. Instead of playing the two C and D rolls together I simply drop down and use the open D string I play CDD highD open DD. It lends a synchopated affect to the overall tune.
This occurs in the second part where instead of playing the high G and A rolls together I play GBB ABA. Again this helps break up and vary the bar. The true affect of the variation will only be experienced when the tune is played a number of times around.