Hey man - this may or may not be helpful, because I don't actually know the change - but when you have the problem of multiple cards sliding, usually one thing to work on is a lighter touch, treating the deck of cards as a delicate object.
Again, this may or may not help, but I'm sure you'll get some more specific responses in the next day or two. Sorry I couldn't be of more help, but yeah, on the off chance it does, thought I'd post it. Good luck with the sleight.