First because involving all the chicanery of accounting to figure out my fee is asking for lots of resources just to calculate and audit fees.
Second, unpredictable costs are bad. If my company’s revenue doubles in a year, that doesn’t mean that my department’s budget doubles. Or that I even have enough earnings to cover licenses.
Finally, this is hard enough with a single product. My org uses thousands of products. If they all charge 1%, where does that leave me.
PS- morally this just seems dumb. If my grocery store charged me more or less depending on my income or the value I derive from a tomato, I won’t shop there. Just publish a price and let people decide to buy or not.