It certainly helpful and let me change the advertise transmit power . i did test a line of site test with having different TX power set (i don't have required information to measure it precisely ).
and the result shows from -16 to +4 you can see gradually change in RF strength (100 sample each time with 1 sec RSSI measurement using FrontLine PBA 600).
but from +4 to +8 strangely the signal weaker this time i tried (1000 sample for each same environment , same setup).
i used wiced_bt_dev_set_adv_tx_power() to change advertise transmit power. and hello_sensor sample code (i purposely didnt change any thing except adding line to change advertise transmit power )