Exactly correct, but I also think there were two other factors:
1) Ivana's rivalry vs. Jen was obvious. I think she wanted to see Jen beaten more than she wanted to see herself win. She was determined to out-do Jen at something, even if it was out-slutting her.
2) From an economic standpoint, she realized that she had to make up the difference between 290 bars at $5 a pop and 300+ bars at $1.50 a pop. She first tried to sabotage the twins and, failing that, resorted to the only weapon she believed she had left.
Which should lead to another business lesson which is to know when to accept defeat, take your lumps and regroup for the next day.
That's all she did was complain about Jen. Did you see when she went into the losing teams room last week to try to convince them to get rid of her? She was so jealous of her, it was absurd. I thought she would end up talking about "Jen" in the taxi.
She must have felt pretty pathetic when she pulled down her skirt and still couldn't outsell her. Her envy finally did her in.
If this wasn't a set up, and Ivana did that on her own, she is a real idiot.