Inaccurate evaluation

I have subscribed to pro account, have received 7.5 or 8 on all IELTS practice speaking tests. I have practiced ALL exam simulations given and have consistently received 7.5. The exam score was 6, I have expected more depending on the time and practice put in Smalltalk2me simulations. As it appears, the evaluation is inaccurate. It was not worth paying so much money in Pro account.