Per federal regulation 778.419(a), when the overtime rate is agreed to in advance (known as a bona-fide rate), it will be based on the type of work a person performs during the overtime hours. For example, let’s say a person work 35 hours as a teacher and 6 hours as an office assistant (a total of 41). If the overtime was worked as an office assistant, they would be paid at least 1.5 times their normal office assistant rate, as set up by you on their Employee Pay Rate screen.
See also: US Dept. of Labor Regulations – Part 778