I really like my P3, or is it a P2? I read the entire direction manual before setting mine up, and then I read it again. You need to adjust your basic setting before you mess with the boost settings. Once I did that I didn't use my boost at all. After a few trips down long steep mountain passes I realized that I should be using B1 or B2 for some help. This made a big difference in the actual time I spent with my foot on the brakes.
So, set it up properly to begin with and then mess with the boost settings. I don't use any boost until I hit the highway. In the passes I will sometimes go into B2. Works for me, no grabbing and I feel safe.