They don't, some items are per unit, which is a way that avoid comparisons for fruit. In [my local] Tesco they even took away the manual scales now, making comp

They don't, some items are per unit, which is a way that avoid comparisons for fruit. In [my local] Tesco they even took away the manual scales now, making comparison across 5 different types of apples, say, much harder. Good mental-arithmetic practice.