I would have to watch the program again to see the specific moment (I have never seen Phantom) but off and it could be the difference between interpreting the music itself versus portraying the appropriate character. For example if you took Yuna Kim's cut of "On My Own" from Les Miserables - the character of Eponine is very tragic (musical version, not the novel) and it's a very serious song. So if you wanted to portray Eponine, you definitely should not be smiling at that part. But if you're just skating and interpret what the piece means to you, smiling would be perfectly appropriate, because that cut is very uplifting. It sounds like some kind of powerful reunion or recovery moment.