Jill's PPP would be...
Promise: She's going to move from a hoity toity high-class girl to someone who can come out of her shell and be fun and spontaneous
Progress: Dumping Tybalt in public, asking MC out, playing the concert, etc
Payoff: She wears a metaphorical and literal shell costume (a banana) during the party that she...never takes off to reveal something fun and spontaneous underneath.
It really seems like DPC set her PPP up perfectly and then forgot the payoff. The party would have been a perfect place to make it happen too. I wonder if perhaps DPC ran out of time with her. We actually backslid her main promise (coming out of her shell) because she seemed like she couldn't handle the party, couldn't handle the sex, and wore a silly costume rather than something befitting of her personality.