It's definitely a change or alteration of components. I posted this video because I thought that the discs sold here (Singapore) were different (both using a new set of batteries):
http://www.youtube.com/watch?v=rZSeVP4Dymg
Then a friend got a Sam's disc from the US and it sounds just as the one sold in Singapore.
So I guess the only ones with the faster sequences were the ones from the 1st wave.