CC2640R2F: Can CC2640R2F reduce TX power to less than -21dbm?

Hi Team,

          My Ctm uses CC2640R2F for their beacon product.Different from the traditional beacon. Their beacom is used in check-in applications.So that the communication distance should be as close as possible(about 1-2 meters). Now ctm adjusts the tx power to -21dbm but the communication distance is about 20 meter . It's too long for thier applications.

          Can CC2640R2F reduce TX power to less than -21dbm? How to do?   If can't , How can we  reduce the communication distance unceasingly by software？

           Many Thanks！