I don't remember my individual Math Destroyer tests, but I think you should just continue chugging along, and don't focus too much on the scores, but focus on the material itself.
If you feel a bit more confident about the material, then you're probably getting better. You may be getting better because eventually you'll see word problems that test similar concepts from different angles in each test.
Just keep working on them, and you'll be fine. 🙂 Math Destroyer is harder than the DAT, but the concepts are similar.