I can confirm that while running Version 2.56.1, I can control subquestion relevance. I've set it up to reveal up to four subquestions depending on the answer of a previous drop-down list. For example, choosing "two classrooms closed" will display two records on the array of texts.
See attached "array of texts relevance.png" to see where the Relevance Equation is actually added.
See attached "array of texts relevance.png" to see where the Relevance Equation is actually added.