Sirens vs Penelope

I know the lovely voice of Anna Lea sings the siren's song, as well as her character of Penelope. But even with the same voice, they seem like two different people. Am I crazy? Anyone feel this? Like we know it's the same voice, Suffering gives the vibe I her voice that she's not Penelope but a copy of Penelope. Her voice in Suffering is so slightly different from her voice in The Challenge and WYFILWMA.