There's no audible difference between signing "she's said" and "she said", the s's blend together. Any possible difference would be entirely obscured by stylistic choices.
Even vocalizing normally the difference is hard to tell. Try saying "She said I love you" vs "She's said I love you" – unless you make a point to completely stop in between words there's basically zero distinction.
Isn't the grammatically correct rendering of that line "she _has_ said goodbye too many times before"? (Present Perfect, right?)
Now I'm curious to hear the recording: is there a sibilant, "she's"?
Edit: Several others made the same point below. I'll leave this here, but they were first. /e