Because it will give you a wide range of problems. The last 3 are more difficult, but do not worry so much about timing, know how to set the problems up quickly.
If you have time go through all of the Math Destroyer and search for problems that are your areas of weakness.
Hope this helps, nothing is more tragic than a low QR score that results in a retake!
Wishing you the best..What day are you taking the DAT!
BTW, love your Batman picture...I watched the original batman show when I was a kid.