@Firgal Good day, 

It is recommended to change a different wall socket for the powerline unit. 

Please put powerline units in the same room and see if Powerline rate & real speed improves or not. 

tpPLC Utility shows the Powerline rate which is an indicator for the powerline environment. 

If the powerline rate is below 30% of advertised power line rate AV1300,  powerline environment is not so good and  powerline devices may get unstable/ slow speed. You could follow this instruction and remove the things that may affect the power environment:
https://www.tp-link.com/support/faq/409/
( AC power adapters or electrical devices with a motor such as air-conditioners, washing-machines, electric-fans etc., put them far away from powerline devices)

The real speed is around 30% of the powerline rate, in the actual powerline environment, the conversion is normally 20%-30% .(the actual conversion rate depends on the electric wiring system). If your real speed is around 36mbps, that in the normally range. 

Here is a related FAQ that may help : Explanation about the Powerline Rate and Actual speed of the Powerline Adapters
https://www.tp-link.com/support/faq/2928/