Does TX power decreases with decreasing battery life?

[Ans Hafeez]

After some search I found that accepted values for tx power are -40, -30, -20, -16, -12, -8, -4, 0, and 4 dBm.

So my questions are

1. once I set the tx power using "sd_ble_gap_tx_power_set()" function then tx power remains same until the battery completely die or it continuously decreases with decreasing battery life.
2. If it decreases with decreasing battery life then why there are only few accepted values in above mentioned list.
3. Is there any difference between rssi values at 1 meter with
   vdd=3.3v tx=0dBm and vdd=3.0v tx=0dBm?

Many Thanks.

[Petter Myhre]

1. It remains the same.
2. It is not.
3. No.

[Ans Hafeez]

Thanks.....