That is exactly what it means, and if you can complete ALL the work in the current DAT and Math Destroyer and feel comfortable with that level of work you will achieve a high DAT score and Destroy the DAT Beast, but there are NO short cuts do every single problem.
There are no guarantees. In my case, DAT Bootcamp + DAT Destroyer helped me get a 29 total science score. Your mileage may vary based on work ethic, and study strategies. If you go through the Destroyer at least 2 full times and understand EVERY question and their explanations, you will likely get above a 20. If you can afford it, extra coverage from DAT Bootcamp will also be very helpful. There's no such thing as too much practice problems. Don't bother with timed tests until you master Destroyer though as they are a poor use of time in the early phases of studying.