Yes. This is because majority of students tend to do well studying alone and not with friends. Group studies are beneficial to students who require extra coaching but not everyone needs that. Exam preparation leave is important as this allows student to study at home at their comfort instead of going to school only to come home exhausted. Preparation before major exams usually involves minor revisions of certain subtopics of a subject and focuses mainly on doing model or past years papers. So technically, a student doesn't require any more of group study session as it is more on exercise basis now in preparing for major exams.

( not much but I hope this answers your question )