That may not be PWM. My (cheap) induction cooker seems to do actual high frequency PWM at medium-to-high settings, where the heat is essentially always on, but varies total power. It seems to cycle at lower power settings, with multiple-seconds of on and off. “3” is always on; “2” is 5 seconds heat + 10 seconds off. No clue why it would switch modes like that. I’d assume it’s a manufacturing cost, but it means they had to implement both PWM and slow cycles.