I am using the test firmware in KBA220073 and noticed that the default transmit power level is set to 3dbm. We are using our BLE at 0dbm and are going to go through the certification process. Is there a regulatory reason that the transmit power level is set to 3dbm?
Yes, the reason is regulatory tests only, which requires test cases to be executed at maximum power level. If you don't plan to use 3 dBm in the application and the maximum you will ever use is 0 dBm, then you can certify with 0 dBm setting.