It’s like if you got a raise for any reason, figured out what you’re going to get on your next paycheck and when you get the check it’s not on there. She got $308 instead of the $400 she was expecting in gross pay. She believed she was performing the labor at the higher rate.
What we don’t know is whether or not she may have turned down jobs in the burbs that paid in the $9 an hour range during the time she was expecting her current pay to rise. They would have been harder to get to, taken more babysitter pay to allow for travel time and still have been worth it otherwise.