Thank you for your replies.
If all of the 9 experimental questions are wrong, would the score be effected ?
I don't think so. But obviously, it is a moot point - you can never tell which one is which. You will have to give your best shot on every one.
On the OP - yes those are 700+. I'd suggest you compare your performance on the last 25 questions in the OG with this performance.
and Dabral is right, can't judge much on the half wrong statistic. I'd still go ahead (make a fool of myself) and say its a decent attempt. You should be looking at late 40's (possibly a 50) with that performance.