Here's what happens:
- The maximum conducted transmit power in 5GHz on an AP-124 is 17dBm (per chain)
- The applicable regulatory limit for the AP-124 when configured for operation in the US, is 30dBm in the U-NII-2 and U-NII-2e bands
- Because the AP-124 combines (diplexes) signals from both bands (2.4GHz and 5GHz) on a single set of connectors, there's some additional loss between the radio and external connectors. In 5GHz, that's 1dB
- The way the software reports this loss is by adjusting the provisioned antenna gain, so the remianing gain is 4dBi
- Resulting EIRP is 17 + 5 - 1 = 21dBm
- The AP-105 has significantly more transmit power available than the AP-12x