Hi All,
am practicing the cccure practice questions for my exam preparation. But when i keep difficulty level to Hard, am getting upper 80s or sometimes 90s as well. But when i keep difficultly level to Pro, am getting lower 70s

am not sure where its going wrong. Pro level questions are very tricky and confusing. Could you please suggest to improve myself.
Currently am using CISSP AIO, Eric Conrad Study Guide for my preparation.
Thanks in Advance.