The PicoVolt is not meant for extremely precise applications. All motors have some degree of "drift" and you may notice some variation in your program over time. This is normal.

For example; You program a prop head to look left and then right with the PicoVolt.  The head will eventually be looking backwards due to motor drift.  This is because there is no feedback to the PicoVolt from the motor to tell it that it is "home".  The motor and controller simply do not posses this ability.  The PicoVolt tells the motor to stop but the motor takes a bit to actually stop.