But in this example the important thing is the trust point even if it means that Carol also adds a nerve point. Trust is key with Carol. Reading the walkthrough, in this chapter there is a branch (trust<4) where she hates the MC presence for not being sincere with her through the story (besides not getting the h-scene of the chapter). What I mean is that in the game nerve points are obtained as an extra to a decision that adds a trust/love point, or because it's better to gain a nerve point than to lose a trust/love point. But if there is an option that allows you to lower a nerve point without any consequence, why not choose it?
And like
Wolf Plays™ said, I'm not criticizing the great work you've done here and in other games, I'm just giving my opinion about a doubt that has come in the thread (and that in the "original" walkthrough is selected as "Choice with most positive outcome").