Kapan complete text- expandable text

Hi there, I’m starting out self-studying P2 for the December 16 sitting. I have purchased the kaplan complete text and I’m wondering if it is worth spending time on concentrating on those areas which are expandable text which are classified in the book as “additional information about a topic area”. Is it worth spending the time to learn these parts, i.e. can a written question be based on a topic in this area?