The answer from Herman in that topic should conclusive. The values you see in ArubaOS are EIRP; this means antenna gain is accounted for; in other words: this is the value after antenna gain.
For AP's with internal antennas ArubaOS already knows the antenna gain, but when working with external antennas you will have to configure the antenna gain during AP provisioning. This way, ArubaOS can calculate the correct EIRP so local regulations can be met.
If you want to know the actual TX-power on the radio side of the AP you can look at CLI commands like: "show ap debug power-table ap-name <AP> radio <0 or 1>"