From section 3.3.2:

... The by modulators are processed in a round robin fashion. So even though there are three values we want to have formatted, we only need to specify two by modulators as both the first and third values are the same...

Is this correct? As I understand it, the values (i.e. 'LCY' and 'MAD' in the first result) are different, but the selected property ('code') is the same. So we are having three output values but only two types of output values.

This might be a semantic issue. In common sense, the strings 'LCY' and 'MAD' are values proper while the expression "values('code')" is a command to return these values.