Question about the reliability of NCSBN learning extension review

Hi all! I have attempted the NCLEX 1 time and hate to say that I failed around 160 questions. I am scheduled to take it in 4 days (eek!) and have been using the NCSBN Learning Extension 3-week course to study, along with other materials to supplement. My question is this: How similar is this course to the NCLEX? I guess my main inquiry is because I am scoring an average of low 60's on these tests and quizzes. I feel very nervous because if this is similar, then this wont be good enough for the NCLEX! Has anybody passed the NCLEX using this course and if so, how were your quiz scores going through it? Any and all advice is much appreciated!! Thanks!