When you run the WLAN Pros Toolbox and the number it gives you doesn't match whatever internet speed test you were looking at five minutes ago, the Toolbox is not wrong. Neither is the speed test. The two tools are answering different questions, so they return different numbers, and both numbers are correct for the question they answer.
A speed test and a Wi-Fi test sound like the same thing. They are not.
An internet speed test opens several connections to a nearby server and fills the path until it's full, then reports how fast it ran. That path is your Wi-Fi link, plus your access network, plus your ISP, plus the peering between your ISP and the test server, plus whatever congestion sits anywhere along the way. The number you get back describes the whole journey to a distant machine. It is a real and useful number. It just isn't a measurement of your Wi-Fi.
That distinction matters because the most common Wi-Fi complaint in the world is "my internet is slow," and most of the time the internet is fine. The bottleneck is somewhere else. The job of the Toolbox is to tell you which side of the access point the problem is on.
So the Toolbox does not try to reproduce a speed test. It deliberately isolates the Wi-Fi link from the internet path and compares them. That design choice is the reason the numbers differ.
The Toolbox does not hand you one number and call it your connection. A latency problem and a loss problem are different problems with different fixes, and a single throughput figure hides the very thing you opened the tool to find. The tool shows you each dimension on its own and tells you which one is the ceiling.
If your internet is comfortably healthy on throughput, latency, and loss, the tool says both sides are fine and stops there. The ratio between the two localizes the ceiling. Internet much slower than your usable Wi-Fi capacity, and the verdict points upstream: it's not your Wi-Fi. Internet running close to or above that capacity, and the verdict points at the link: it's your Wi-Fi.
Once you accept that different tools answer different questions, the rest falls into place.
The speed-test habit goes wrong in one specific way. The reflex is to run a speed test everywhere and read off the one big throughput number, without asking what that number is even measuring. It's measuring the whole path to a distant server, not your Wi-Fi. That's why the Toolbox doesn't reduce your connection to a single speed number at all. It separates the Wi-Fi link from the internet upstream and tells you which side is the ceiling.
When the Toolbox number doesn't match your speed test, that's not a bug to explain away. It's the tool doing the one job a speed test can't. It's telling you whether to call your ISP or move your access point. Different tools, different questions, different numbers, all of them correct.