How 'Umpire's Call' affects the DRS appeals in cricket?

'Umpire's Call' is used in the Umpire Decision Review System in cricket to give the 'benefit of the doubt' to the on-field decision in case of inconclusive technological evidence. As per the latest rules, the on-field 'umpire's call' on LBW reviews stands if less than 25% of the ball is hitting the stumps, excluding the bails.