It's not that unusual in the antitrust context. The whole theory of antitrust is that anti-competitive behavior allows a company to charge prices greater than they would be able to charge in a competitive market. If a company is found to have engaged in anticompetitive conduct, it's common in a civil suit for the measure of damages to be the difference between the prices actually charged and some judicially-determined market price (usually based on an econometric expert analysis).