I just breezed through the K&B once but did a lot of mock exams from Enthuware averaging at around 85%-90%. I learned faster in mock exam rather than the book because Enthuware provides explanation for answers outright. That took me two months to prepare and practice with my Netbeans programs.
I think the real exam were easier but questions were just really tricky. Finished the exam in 1.5hrs.
I hope to do better in my next exam to follow, OCE-JWCD 6, hoping to score at least 90%.