@wends,

Powerline is a different beast in itself when it comes to home networking. 

Are the higher speeds that you are seeing, the potential link speed of the network? This would mean that it is essentially the bandwidth that the devices can support in their current physical configuration. Real Life speeds will be entirely dependent on additional factors such as connectivity, range, and electrical interference. 

Have you verified that your device is connecting to the satellite node wirelessly and not the main node or main network?

The first step would be to move the satellite nodes to see if the behavior persists across setups. Next, I would move the node to the same room as the main node, this will allow you to ensure that the device is working correctly.

  @wends,

I was able to find a FAQ that included a few settings that you could fiddle with to see if you can improve the connection quality: Troubleshooting Slow Powerline Speeds;

Otherwise, the first step is to move the devices around to make sure that the devices can function correctly in your environment. However, looking at some of the internal documentation we have for the utility, it does appear that the higher speed that you are seeing is something like that Link Rate between devices. There is a conversion rate for PLC devices that indicates how much of the bandwidth is actually being converted to a datastream. For most of the devices, the speeds that are expected are similar to your setup. PLC connections that have larger bandwidths require a PLC system that is capable of handling well above the expected speeds. 

From what I am seeing, it is a good idea to treat Powerline Connectors as Range Extenders, as they seem to experience the same falloff as a Range Extender