Qectel BG95-M2 - FTM mode - power setting

Based on BG95&BG77&BG600L Series FTM Application Note it seems that too parameters control power transmitted in NB-IoT mode: rgi and power. I’ve tried to set the output power as low as possible, but the lowest valid setting was 0 dBm for power. Is it any combination of rgi and power settings to set power below 0 dBm?
Thank you,