Contrastature

Both of these interpretations could account for the use of and, and neither presents anything that seems testably false, so the best criteria for judgment are probably that the second approach is more elegant and would probably be easier for a person to learn.

One last bit of interest is how to deal with the word respectively in the two cases. In the first case it's quite simple, as respectively is an adverb affecting the main verb, and it can just transform that verb to one that always matches arguments as they come. In the second it has to change function application over the boolean and so that only the respective interpretation is allowed. That's a bit of a strange thing for an adverb to be doing, unless we think of it as a comment to remove ambiguity. It's analogous to me adding habitually to ``I'm happy'' to distinguish between the two ambiguous ``generally happy'' and ``currently happy'' interpretations.