The originals were bred for low blushing, but then he started to see some with higher blushing and started line breeding those, to discover the fader gene.
My male is one generation removed from NERD and confirmed by Kevin. I checked with him that he did sell my male's sire to the breeder that I acquired him from. Kevin's also seen pictures of my male and his daughter and thinks that they both may be fader, and in his opinion are confirmed NERD lemons. More breeding will be required to draw any definitive conclusions.