Gigablast Upload Speed Reduced

A couple of months ago, our family upgraded to the Cox Gigablast Internet package. Over the phone, we were promised Gigabit download and upload since we live in a new neighborhood with dedicated FTTP service. The Internet speed has always been sufficient as what was promised, however today when I did a speed test, I only got ~70 Mbps upload. A few more tests averaged only about 30-70 Mbps, sometimes a bit more. Has something changed? I don't believe it is any of our equipment.