No, it's not necessarily that we assume that. It's just one rate that you would take into account. Another rate that you might take into account is the return a corporation could earn on those dollars had they been able to retain those dollars.
It's just not black and white. You're trying to balance fairness to the taxpayer against fairness to all taxpayers. To come up with a reasonable amount of interest that should be paid to a taxpayer, we wouldn't take into account just what the government's borrowing rate is, but a number of different borrowing rates.