Text: The upward leaping orchestral figure anticipates the word, top, but the sung line does not, and at the punchline, But if Baby I'm the bottom, / You're the top, both Billy and Reno (I'm and You're) share a melodic line at the top of their respective ranges.
Entailment: Billy and Reno sang a melodic line together.
Contradiction: Billy and Reno both sang at the bottom of their respective ranges.