Well, don't think of it as 2 different arcs. Consider it as a circle. Use the up and down arrow to change the direction of the circle or the 'arcs'.
Placement feature is similar to tilting your wrist when playing a shot. For eg, if you play a cover drive with the placement circle turned all the way to the clockwise direction for a right handed batsman, the shot will be played more squarer than the usual cover drive. Similarly, if you turn it all the way to the anti clockwise direction for a right handed batsman, a cover drive will go a lot straighter than usual, thereby helping to pierce the infield.
Hope that helps.