The rotary control is not pointing to the maximum power level.
Check whether the marking on the rotary control is pointing exactly to power level 12. Between 12 and 0, the ProLine element operates with reduced power.
The ProLine element does not get hot enough on power level 12 for the food to start browning.
Check whether the marking on the rotary control is pointing exactly to power level 12. Between 12 and 0, the ProLine element operates with reduced power.