[magnets]

You should probably be fine. Your robot will run for maybe 100 hours the whole season, and that 422 oz in torque rating is in place because that belt is designed to be run with that much torque for thousands and thousands of hours.

When doing FRC design with bouncing, vibrating, and crashing robots, it's important that you build in a safety factor for shock loads, but fatigue over thousands of hours isn't usually a problem.