LimeSDR output power during GSM set up

Dear forum,   I am setting / running GSM network with LimeSdr and Osmo-packgaes: osmo-bts-trx osmo-bsc osmo-hlr osmo-msc osmo-pcu osmo-stp osmo-trx-lms   and as i understand the only option to vary / set up output power is through the → osmo-bsc → trx 0    nominal power 23    ! to use full TRX power, set max_power_red 0    max_power_red 20   So does this mean that 23-20=3 dbm? With this set up i instruct LimeSDRmini to transmit 3dbm signal into the air?  If so — when i brought phone just into the very vicinity of LimeSDR antena (touching phone and SDR antena) on my smartphone screen i got signal -60 dbm …why did i get such a low figure ?     Also if you know is there any supporting application / software that can tell at what dBm LimeSDRmini is sending RF into air?   -- Mario Lucas