You see.... I was thinking the same thing. The article didn't go too deep into the explanation either. My Charger has the MP conversion, so does the FrankenDuster. I'm keeping them as is.
The Chrysler engineers decided to implement a different ballast when they integrated the electronic system in 1972. Why spend the $ to develop a new part if it was unnecessary? I'm not saying that the factory never made mistakes, but I'm going to "side" with the factory on this one.