With a cast of Roll the Bones with Grand Melee, Slice and Dice can get extended to be around 2 minutes long. Even with that MaxDps recommends casting a new Slice and Dice. At that point it's not castable since the existing Slice and Dice is too long. This gets pretty frustrating as it blocks the rest of the rotation from continuing. The only way that I've found as a way to get around it is to cancel the existing Slice and Dice.