I have a microwave from the Etna brand that has a big flaw in the UI. I believe the software is reused in many microwaves because the cheap ass microwave from the Lidl my parents have has the same interface.

The flaw: In the first step you need to select the amount of heating. Not in absolute numbers but in the percentage of total power (100, 80, 50, etc). So every time you need to calculate how much power each percentage represents.