When using this setting, the geometry controlled by the parameter is scaled or stretched along both the x and y axis keeping the proportions of the geometry the same. Each point in the adjustable point set is moved by an amount based on its relative distance from the anchor. Points closer to the anchor are moved a smaller distance then points further away from the anchor. For symmetric parameters, the anchor is the center point between the two reference points.
The scaling factor used is the ratio of the new nominal value to the present nominal value. Each point is moved by a delta calculated by multiplying its present distance from the anchor point by the scaling factor.