What are the two speed settings on the BCD704C1 and when should I use each one?

The BCD704C1 has a dual-range gear feature with two speed settings. Position 1 (low speed, high torque) is selected by sliding the speed change button away from the chuck, and Position 2 (high speed, low torque) is selected by sliding the button toward the chuck. Always turn the tool off and let it stop completely before changing speeds. (Page 9-10)