Instances? As in, it happened a single time and may have had some sort of extraneous factor? Or do you mean it consistently happens? I ask because time after time after time the people with the greatest TO speed have the longest jumps, just like how in the 100m whoever hits the highest top speed is, without doubt, the number one determining factor in who wins the race and the finishing time. Does that mean reaction, acceleration, and speed endurance mean nothing? No, it just means that they are far far far behind top speed in terms of importance, though many aspects are quite related and dependent upon it in the first place.
If you know exactly what the authors have said, you sure aren’t showing it because they did not say that speed was statistically insignificant. Hell, Graham-Smith has even put out some theoretical equations on determining LJ ability based solely on speed.
I am also quite confused on how something that you say is the biggest determining factor is not the most important factor on its own.