this one comes up a lot, and eventually a tweeten guy said outright it wasn't a change in formula, just a change in packaging. I can't swear by this but I think he said it was due to 9/11... which completely makes sense, you starting seeing flags on everything after 9/11.
I stumbled across a cube and played with it, it was just chalk.
Always apply this simple straight-face test when people talk about how some magical piece of equipment helps their game:
Your opponent just missed a ball or dogged his position.
He says to you: "That wouldn't have happened if I'd hit that ball with preflag master instead of regular master."
Do you accept this as a valid excuse? Or laugh in his face?