I had a similar experience with PR CAT 1.
I got only 5 wrong in verbal yet I got 35...
Remember that it's CAT, the harder the problem, the more points you earn by answering it correctly.
From what I see, since you were able answer all questions except for 1 in the beginning correctly, you were given much harder quetions later on and so although you got 8 wrong later on, it didn't lower your score that much.
On the other hand, I presume the 5 incorrects that you made came mostly from early on, so you were given with easier questions which you were able to answer correctly, but which didn't really help in boosting your score.
Hope this explains.