I dont trust any speed test results from gaming consoles. They are designed to play games, not run speed tests.
Could be the server they use, demand on server, routing issues to server, etc etc etc.
I have run on a lot of service calls for speed issues on wifi just on gaming systems. Its common for a gaming system to say 7-15 mbps either hardwired of on wifi, and then run a speed test on a laptop using either the exact same cable, wifi setup, and in the exact spot where the gaming system is and see over 90 mbps on the laptop.
And also if one device is rated for gigabit speeds and the other is at 10/100, you will see a big difference on speed tests especially when you are looking at very high speeds