Where I grew up they taught us this thing called algebra, where you can quantify different things in different ways. There's also these things called exponents and percentages, which allow formulaic calculations to quantify those items in specific factors.
These concepts were in this umbrella of a thing called mathematics.
Your argument is now becoming comical. Putting different weight on different factors is something that literally occurs in every single walk of professional life. I don't know how you don't follow that concept, its quite possibly the single most basic concept of workplace interaction.
The "variation of weights" as you put it, is calculated very specifically, and formulaically, in the link I provided you. Since you seem to have missed it, here it is again:
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