Whenever I hear an actor say a line the same way he said a previous line, I know he's holding on to a previous moment and not truly in the present moment. True, it's more difficult at an audition when you really don't have another actor helping you. You have a casting director who may or many not give you much. And they may themselves be stuck in a moment, the moment of "Where's my lunch???" That's why you have to push yourself to go to different places.
React spontenously to what you hear, what you see, or even what you yourself are saying, in order to push yourself to a different place. And it doesn't even have to be what's happening in the scene. You could react to something in the environment of the office you're in, the way the clothes feel, a taste in your mouth. Any stimulus that comes to you is a gift -- react to it, see where it takes you, rather than shutting it out in favor of where you THINK you should be.
Keep taking the risk of being in the moment and not knowing what's coming next. Don't tread water throught the entire scene. Keep getting back on the diving board and diving in, not knowing what's below you.