This mock exam somewhat helps me to pass the exam although not able to achieve the idea score that I was hoping for.
I started with 65% when I first took the mock exam. Did it for two weeks and able to boost to 85%. Of course my score of my actual exam is less than that.
You still need to refer back to your reading material for IASSC BOK to get yourself familiarized with the tools and knowledges required for an IASSC ICBB. The exam covers not only that but also your work experience. If you have been doing this full time for some time you should be able to score higher. I am not saying this mock exam not being helpful. It does help by improving my initial score by about 20%. As long as your expectation is to get familized with the text format you should be fine.