You're not alone. I pay for the 500 mbps service yet it's rare that I get much above 300 and in fact right now, I am getting less than 200. It's very inconsistent with the majority of time being way below what I pay for. I've called tech support and spent countless time with them with no resolution.
Post the requested info from here;
Thank you EG however I honestly do not think there is an issue anywhere on my side of things as I have done many of those things in your link. This morning I am getting 470 Mbps and that is pretty typical for early in the morning (6:53am PDT).