Perhaps the next time you start seeing signs that the day is going to go badly you should let her do her work to earn whatever you give her and then abruptly take her home. If she asks, you can be honest and why she's going home early.
Perhaps it's time to stop offering the help, even if she's earning it. Seems like she's getting paid quite a bit to do some yard work. I understand I think why you're doing this.....but I don't think it's helping her to "get It" simply because it's from you and husband and she still believes she's entitled to it, like just another child living at home.
Hugs
