Awful peak-usage speeds in Gainesville, FL

For about the past 2-3 weeks, I have been experiencing EXTREMELY slow download speeds during peak usage hours. From about 2pm until about 2am, download speeds are somewhere in the 2-4 Mbps range. Upload speeds seem normal. Service is fine at about 6am (getting 18-22 Mbps down), but that's not when users expect quality service delivered. We're on the preferred (18 Mbps) plan.

I had a tech at my house on Tuesday. I was informed that the signal levels are fine. The modem is plugged directly into the box on the back of the house -- no splitters -- and being plugged directly into any computer or through the wireless router produces the same results. 

What concerns me is that I have friends in different parts of the city that are experiencing similar results. I'm sitting in a friend's apartment typing this who has the preferred package as well, located 2 miles south of my house, and also is only getting 3 Mbps down during peak hours. I've been testing it all afternoon -- started out around 8-10 Mbps at about noon, and has been decreasing since. This is the same thing that happens at my house.

This all coincided with all of the students returning to the city for fall semester, yet there's no mention by techs or customer service of a backed up node, or any acknowledgement that there's even a problem. Just that I "should be getting service just fine". Well, I know I should be, but I'm not. And I'm not alone. Every time I've contacted customer service, which has been repeatedly for the past couple weeks via different methods (phone, email, Facebook, Twitter, and now this forum), no one is "aware of an outage in my area". 

Point is: what's going on?