I've read reports/reviews that the OEM pads are using a new formulation that doesn't dust nearly as bad as the old ones did.
Never heard about it going the other direction, though. Maybe you had the newer pad formulation adn your dealer/shop had older stock?
I've been reading up on pads and rotors since I need to replace mine soon. Ended up going with Centric High Carbon performance rotors
and StopTech Street Performance
pads. We'll see....
Oh, and for everyone's reading pleasure, I found this set of articles by Stoptech/Centric to be interesting. Brake and Rotor Bed-in Theory.
Not only why, but how, to do it. Bunch of interesting articles on braking topics on that same site.