I don’t sell software so this is just theoretical. But I wouldn’t want to know my customers’ revenue. That’s too much work and not my business.

I also wouldn’t buy software that had a cost contingent because I wouldn’t want that kind of relationship with my software vendor. Of course, this happens now with enterprise software where a big company will get a quote for $5 and a little company will get a quote for $1. But having something explicit is illogical since software is a near zero marginal cost product.

But even for real world stuff, I’d never hire a gardener who charged differently based on customers income.