The AFT cyberexams are a good representation of the real thing. Finally passed just recently. I reckon you want to be getting around 85% to 100% for the AFT practice exams though.
The CASA Flight Planning exam is a farce. Accuracy to around 200kg for a jet that carries 20,000kg is bananas - especially under time pressure. They should be teaching the theory (thoroughly), not how fast you can punch numbers on a calculator without making a mistake.
But everyone already knows that...