That's what happens when get to buy a company with a fixed price government contract at a low-ish multiple of the contract value (fair enough price based on the contract), that you can get revised to let you charge end-users for the service months later in a field that's growing at a ridiculous rate.
Network Solutions was getting paid per registration even under the original contract; it's just that it was originally the National Science Foundation that was obligated to foot the bill for each domain.
That's why the government was so eager to renegotiate.
