This might be the case for some electric cookers but not all.

I ran a short experiment on mine. A Beko model D 532, solid plate electric hob. Power consumption was measured with a home smart meter. Each time the ring was set to a given power setting, the power consumption reported by the meter changed within a few seconds then stayed stable over the course of a minute with variations of only +/- 10W at most. The maximum power measured of 1950 W reasonably agrees with the manual which lists a max 2000 for that ring.

Any "bang-bang" control would have to switch on and off on a timescale of seconds or shorter while making no audible noise.

Without disassembling the cooker I cannot say how the control is done, but how it could be done is with multiple heating coils within the solid plate and only some are used at lower power settings. The control "clicks" between numbers with in-between setting not possible, which would be expected with such a control method.

The oven, on the other hand, has a continuously adjustable control. It uses bang-bang control with a thermostat, which is a common approach for thermostatically-controlled heaters. The oven is aiming to maintain a certain air temperature, by contrast the hob settings are for a certain heat output.

Full numbers. All rounded to 10 W with errors of about +/- 10 W.

0: 300 W (Edit: This is the consumption of the other electrical appliances in the house, so needs subtracting from the other figures to get the power used by just the cooker. I checked during the middle of testing and again at the end and it remained consistent.)

1: 500 W

2: 540 W

3: 610 W

4: 1150 W

5: 1440 W

6: 2250 W