LHG HP5 Transmit Power

Hoping someone can clear something up for me. I recently purchased a couple of Mikrotik LHG-HP5 radios for a 15km point to point link (the US version). I understand the frequencies are locked to 5170-5250 / 5725-5835, but is the power severely curtailed as well?

When operating at a frequency of 5180, the US version of the LHG HP5 runs with a transmit power of 0dBm, however, the non-US version runs with a transmit power of 21-28 dBm (depending on the modulation selected. Is it normal for the US versions of these radios to run with such a low power output? I was my understanding (based on the spec sheets) that the only restriction was the frequency range, not the total power output.

I have never used US units, but according to FCC grant, https://cdn.mikrotik.com/web-assets/product_files/NII_TC632912_171144.pdf,
the allowed power is 0.12W for 5180 - 5240 MHz and 0.182W for 5745 - 5825 MHz. That works out at about 20.8dB allowed on 5180MHz.

FCC rules in general allow op to 30dBm for point to point in the 5GHz band provided antenna gain is not more than 23dB, and 1dB reduction in power for every 1dB of antenna gain above 23dB. https://www.air802.com/fcc-rules-and-regulations.html