Tit for tat step daughter, need women's advice

My 18f step daughter has recently begun to exchange her nudity for favors from me her stepdad. The advice I seek is from mothers and parents. Should I tell my wife about what her daughter is doing, or keep it secret? The possible outcomes I see are:

1. Wife tells daughter to stop doing it, which is not what I want to happen.
2. Wife is interested in seeing how far her daughter will take it and becomes a silent accomplice.
3. Wife gets pissed at me.
4. Wife waves it off as nothing.

For context, my step daughter has been walking around the second floor of our house from bedroom to bathroom naked at an increasing rate over the past few years and my wife has never said a word to dissuade her. My wife typically laughingly apologizes to me when her daughter does it, saying "sorry she flashed you". But she's never put a negative spin on it towards her daughter.

The instances of nudity in exchange for something started yesterday when she stopped to converse with me while partially covering her naked breasts. She did it a couple times and asked for me to let her stay home from school. A key beginning to the event was when she unlocked her bathroom door and cracked it open before taking her shower. This is something she has never done before.

Today, she cracked the door again, then called me to her when she was again covering her naked breasts in the hallway. Soon after her little show, she asked if I could get her Starbucks on the way to school.

Two days in a row, she's shown tits to gain my favor. Wife was already gone to work both mornings. I figure if I tell my wife about it in the next few days, I should still be considered as not having witheld anything. But I don't want her to shut it down, so I could keep it a secret, but if she finds out later, it won't look good for me. Also, if she knowingly allows it to continue, then I may feel free to escalate, within the wife's limits. But again, I may want to exceed my wife's limits. I definitely want to escalate, so I am probably better off not telling the wife at all. But having the wife involved and supporting escalation would be the best possible outcome, imo.

Feel free to give your opinions and advice.