Just go in at first to get the wording in even if she switches job before you get to court. Make it tight wording "each parent will call the other parent when they need babysitter over 2 hours, this includes work schedules, vacations, and long outings out of the house. Bio parents will have first right before step-parents or other family members or live in people" Then keep track when you have kids for 3-6 months. Then go back and ask for a
child support mod since you have the months of proof behind you.
You can leave out the step-parent wording and state " bio parents and step-parents may fill in for bio parent within each household before finance, other family members, and non family live ins"