Help With NSM2 on OpenWrt 18.06.1

Hello, I want to inform you that OpenWrt 18.06.1 in NSM2 only shows an output power of 22 dBm when the NSM2 hardware can display 28 dBm. Help PLS, if someone could tell me what I'm doing wrong, it should be noted that I've tried all the regions and it stays the same