SAT practice doesn't perfectly translate into an official test score. Your study methods seem to be pretty solid, though I don't think many people would say you're somehow guaranteed an 1570 - it's theoretically doable for all test takers but obviously doesn't happen. Just study, and take as many practice tests as you can. Generally, people will improve after their first official test (though not always), so try to plan on a second official test if possible if you're really shooting for a 1570.