how to interpret current-tx-powers

RouterOS General
1

Hi

Doing an /interface wireless monitor I get the results below; what does the 23 and the 13 mean in current-tx-powers: 6Mbps:23(13)?

Is the tx power 23dBm or 13dBm?

                   status: nstreme-dual-slave nstreme-dual-slave
                     band: 5ghz-turbo         5ghz-turbo
                frequency: 5250MHz            5800MHz
              noise-floor: -90dBm             -96dBm
           overall-tx-ccq: 91%                100%
    authenticated-clients: 0                  0
        current-tx-powers: 6Mbps:23(13)       6Mbps:23(13)
                           9Mbps:23(13)       9Mbps:23(13)
                           12Mbps:23(13)      12Mbps:23(13)
                           18Mbps:23(13)      18Mbps:23(13)
                           24Mbps:23(13)      24Mbps:23(13)
                           36Mbps:23(13)      36Mbps:23(13)
                           48Mbps:23(13)      48Mbps:23(13)
                           54Mbps:17(7)       54Mbps:17(7)
      current-ofdm-errors: 312                269
      notify-external-fdb: no                 no
2

Tx power is 23, it is shown in such way, because of the tx-power offset.
http://forum.mikrotik.com/t/winbox-tx-power-display-seems-10-db-low/22165/1