You're right. Three years later they reached the settlement that should have been reached the day Limbaugh left rehab.
If the prosecuter had never investigated, he wouldn't have needed a $30,000 re-imbursement.
If he had found something, he would have prosecuted.
Rush had to take this deal, because he's paying a lot more to Black than $30,000, and the 'deal' is essentially a complete dismissal of the case.