Am I missing something or is this not working appropriately? It seems to be simply acting like a mask for the entire effect, rather than modulating the scale. It even says "exponential" which it is not. 0, is no effect, and 1+, is whatever settings you have entered (with a constant scalar). And when you use a PF it seems more or less similar to just using a mask.
Also, the Wiki has not been updated in regard to this feature.
