Task-dependent "reversed" handedness: why use left hand for some tasks? How is it controlled by the brain?
The dynamic-dominance hypothesis of handedness states that the essential factor that distinguishes dominant from nondominant arm performance is the facility governing the control of limb dynamics. Sainburg (1) writes that


  It should be noted that dominant arm advantages do not apply to all
  tasks, or all aspects of tasks. Healey et al. (1986) examined an
  extensive range of tasks and found that four factors or groups of
  tasks accounted for 80% of the variance in hand preference among the
  110 subjects tested. Tasks that were almost exclusively associated
  with dominant arm use included activities requiring precision in
  interjoint coordination and trajectory formation. (...) In contrast,
  tasks that involved spatially orienting a body segment posture were
  more often performed with the nondominant arm. These tasks included
  posturing the hand to point toward a distant object, which is similar
  to other functional tasks such as holding a piece of paper that is
  being cut with scissors, or orienting the hand in space for catching a
  baseball. Such postural orientation tasks are less dependent on
  intersegmental dynamics, since the trajectory used to attain the
  posture is not critical for task success. The dynamic dominance
  hypothesis thus appears to account for the extent to which hand
  preferences for specific activities are lateralized.


This appears to be consistent with your experience.