Support for Mikrotik Hap AC2

There are issues with the 5 GHz wireless performance.
Have been testing the Mikrotik LDF 5 ac, a device with very similar ipq40xx hardware but only 5 GHz and no USB.
Using the ath10k-ct-smallbuffers wireless kernel driver, at least 10 dB of receiver sensitivity is lost. The standard ath10k driver in combination with its firmware, gives rssi level reports similar to that of RouterOS. This was tested in a setup with connection over 7 km distance, while also monitoring the remote location via UBNT equipment..
That is to say, connection in a limited way. No real data transport as apparently the distance/coverage class setting and/or automatic adaptation are not working. This makes the 802.11 protocol break down.
iw phy phyN info (N=0 in my case, N=1 for the hAP ac2) shows distance setting 0. iw is not able to set this. Any ideas how to set coverage class / distance?