Paid to upgrade to 1Gbps, now getting less than previous tier in speeds

I recently upgraded to the 1Gbps plan and found I needed to get a new modem that supports DOCSIS 3.1. I have since upgraded, but now my speeds are LESS than the 500Mbps tier I was paying before. 

I have my own network gear - CM2000 modem and a Netgate  PFsense firewall and decent switches. Cabling is not the issue. I have at least CAT5e everywhere. 

I find when i run a speed test, I am getting about ~370Mbps and have a decently high ping of 15-18ms. 

What is the issue here? If I pay for 1Gbps, I expect to at least be in the 800-900Mbps range with all this nice gear.