Power Level in Xbee PRO S2B

good afternoon, I have a question about the power of the "XBee Pro S2B" in the specification shows a maximum power of 60 mW (+18 dBm) but the settings by XCTU on the tabs Power Level even enabling the Boost mode displays: 0 = -7dBm, 1 = -3dBm, 2 = -1dBm, 3 = + 1dBm, 4 = + 3 dBm, how get to set the maximum power?