xFi doesn't seem to support advertised speeds over Wi-Fi?

​​Hello,​​

​​I ran a speed test from my xFi Advanced Gateway and see that we get 119% of the advertised 1000 Mbps that our plan gives us, which is great. However, over the 5.0 GHz Wi-Fi (standing next to the xFi) we only get 40% of the advertised speeds. See below:​​

​​Since the Wi-Fi seems to be a bottleneck for our speeds, I ran some LAN speed tests using 2 different apps I found on the Google Play Store (Cloudcheck and WiFi Speed Test), these seem to confirm that even if our xFi is reaching the 1000 Mbps advertised speeds for our plan, our devices would at most get 58% of that over the Wi-Fi. See below:​​

​​For weeks now my roommates and I have been experiencing slow speeds that seem to come and go throughout the day. We all work from home and use our Windows/Mac laptops over the Wi-Fi. There might be an issue with fluctuating speeds, but the Wi-Fi appears to be the initial bottleneck. Can the xFi model we have support 1000 Mbps over the Wi-Fi? If yes, could you please take a look at what is wrong with ours?​​

​​Thanks in advance for your help​​