The only reason he doesn't stand and stare at Harry in surprise at the sudden change is that he turns to look at the box of cereal as if he's contemplating on whether or not he's hungry. He definitely is surprised, though, no matter how much it may look otherwise. How can he not be?

"Thank you," he says as he turns back to him, still smiling. "I am not terribly hungry at the moment. Perhaps later."

It's not a lie. He's just not hungry yet, no matter how much he also likes sugary sweet carbs in the morning. Walking over to the couch, he sits close to him but still with enough distance to not make him feel crowded.

"You know, I was thinking... We should all have dinner together. Cedric and Luna as well, of course. To celebrate the victory and all, I mean."