Gigabit download speeds low, but upload is fine

I've had CenturyLink Gigabit Fiber for about two years now, and ever since it was installed I've only been able to get 200-300 Mbps max download using CenturyLink's speed test servers. Upload is usually fine, landing in the 900-950 Mbps range. I've had the technician out, but they say there's no issue since they can plug in their special laptop and get the full speed. However I've tried with five different computers and they all seem to have the same 200 Mbps download speed. Any ideas what might be the cause? I'm in central Washington in case that matters. I've checked traceroute to confirm I'm going directly to the speedtest server instead of being routed across the country.