Is scoring 90% right after reading good enought ?

I have a degree in financail management. I decided to study for 2014 june and i started with FR&A. Right after reading I score around 90%, I am reading both the CFAI books and schweser notes. How much will my knowladge deteriorate ?? Is it normal to score 90% right after reading and then fail ? I am kinda uncertain in the answers I am providing on the Qbank questions so i was wondering if failing with theese scores is normal. My point beeing that i will not permanently retain the knowledge i have right after reading. I do know that you need 70% to pass tho so thats not my question.
I will get tested on FR&A after i finish it of course...