Hi reza52520,
The scoring algorithm on the Official GMAT is far more complicated than most people realize, so it's not worth your time trying to figure it out. Since that algorithm is proprietary, no GMAT company has an exact match for it, thus CAT scores can vary a bit based on the 'biases' involved in their respective designs.
Have you had a chance to do a full review of this CAT? A far better use of your time would be to review each of your CATs and determine how many questions you SHOULD have gotten correct, but didn't (due to a silly/little mistake). Those mistakes are the things that you have to fix to score at a higher level.
How long have you been studying?
What resources have you been using?
What is your goal score?
GMAT assassins aren't born, they're made,
Rich