S did try saying in a sarcastic voice in the early, 'That's a 1,2,3,4,5,6,7,8,9,10' which jut ogt her sent to her room straight away. The good thing about it for me, although as I say I don't use it for everything, is that it gets around all that, 'I'm cleverer than you' stuff because it's not about talking.
For what it's worth, for the author, the time out doesn't start until they've stopped screaming. With S that could be all day until she is sick, so I cut my losses and it just starts from when she's in her room.
I do also like the fact that it doesn't have a material reward. I find reward charts etc very short-lived in their efficacy. For example, she had her baby doll taken away today which she won for sleeping well as she had started waking up for the hell of it (she had one genuine nightmare for which she got cuddled and then just ran wih it). All she did in response was pick up another doll.
Anyway, make of it what you will and feel free to pass it on 
Danny can be very defiant at the moment but I can get round him so easily it's scary. All I have to do is whisper, 'who's my baby cat?' in his ear a few times and he crumbles into smiles. It's a joy and long may it last.