If they tell you to bring something to an interview, you simply have to bring it...that is the first test at any airline interview: Can the applicant follow simple directions?

Generally, you want a score in the mid-90's or higher on the ATP, but who knows.

I agree that the ATP (the school) computer training/testing thing is the solution for you. The first time I took the ATP (immediately after 9/11) I had lots of time on my hands so I studied full time for a couple weeks...I even worked all the flight planning problems, and got a 92%. That one expired, so I took it again a few years later...I did not study, flew an all-night standup (a red-eye really), drove from PHX to ATP at the GA airport, paid $300, spent ten hours (and 28 cups of coffee) in front of their computer, and passed with a 98%.

ATP keeps track of which questions out of that HUGE question bank actually show up on the tests, and their training focuses on those. For many of the problems (flight plan/W&B/Performance) you can just learn to recognize the correct answer when you see it, instead of spending an hour on calculations (to answer one problem).

The one-day cram session is best, because a lot of that knowledge is not relevant to the real world (or an interview) so why pollute your brain with it? Do you REALLY need to know how to do weight/balance/performance calculations for a 727? Use the online gouges to study for interviews.