asanka, treimin is right. You must do a few more mock exams. If you have the K&B book then you must be having the Master Exam. Do that too and Inquisition. Devaka's examlab is a bit tough. Even I failed in the final exam of examlab (got only 61% in that but got 98% in the real exam). Most of the mock exams are harder than the real exam. If you can get around 65-70% on them, then you will definitely score above 85% on the real exam. If you want a score over 90%, then I recommend that you wait for a while and give some more mock exams and try to grab your weaknesses. Then prepare more on those topics and then go for the real exam.
And don't worry, the real exam is really simple. If you prepare more than enough like me, then you will be disappointed that it must have not been that easy