I'm not quite sure how to understand this question. Are you interested in the moral values expressed in the book or how a reader might learn something about the nature of morality by studying the book? Or are you interested in the notion that the value of the experience of reading it comes as you reflect upon the situation of the book after you have finished it rather than during the reading experience?
One approach you might find useful is reader response theory, i.e. that the value of the Lord of the Flies lies in the way, by the end of the story, you respond to the social commentary in the book and ask yourself whether young people you know, freed of external adult restraint, would, in fact, descend into savagery and murder. In that way, your payoff, as it were, for time spent reading the book comes in reflection on its wider implications for how you think about civilization.