A few points to note :-
1. Those numbers are actually, simulation results. In real life, N number of other variables get added up as well.
2. It was officially replied by IR that WAP7 locos can be relatively more effective up to 130 km/h only, w.r.t. WAP5.
3. No matter what the TE is, the loco has to haul its own dead...
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weight first, then the rake :). A big, heavy locomotive weighing around 123 tonnes with 12 wheels and longer wheel base faces significantly greater rolling resistance when compared to a lighter, 78-ton loco with only 8 wheels.
That's why, in railway terminology, there's another term called "drawbar pull". It's the effective force applied by a given loco at the coupling of the rake or drawbar. The drawbar pull is very similar for both up to 130-140 km/h.
4. In the pic shared by Pratik sir, there's no mentioning of the horsepower of the locos. I'm assuming that the HP considered were continuous HP and not maximum for both of them. Only for P5, you can see another column mentioning the 'increased' HP (4.5 MW) which is the max HP of course.
5. For WAP5, TE values up to 160 km/h are mentioned and, for WAP7, 140 km/h only.