Powerline PLP1000 not doing gigabit

Powerline numbers are even more inflated that wireless numbers in my opinion. The good thing about them though is they don't fluctuate a lot. so the connection you get, is usually solid/reliable. 

If you read reviews on 1000mbps powerline devices, even in an optimal configuration, they won't hit their advertised speeds. Then add in "non-optimal" like a home and put the powerline devices on seperate circuits or with devices that cause interference and their speeds drop further. 

I'd recommend reading a few performances tests on powerline. 

Here's one for netgears PL1200 (a little better device) 

https://www.smallnetbuilder.com/archives/lanwan/lanwan-reviews/32717-netgear-pl1200-powerline-1200-reviewed