I also suggest that you look at Ragsdale v. Wolverine, a US Supreme Court case from 2002. In it, the Supremes clearly determined that as long as the lack of notification does not result in your losing benefits which you would have received if you had received the notification, the failure of the employee to provide notification is irrelevant.

Unless you are prepared to show that if your employer had notified you that FMLA was the first 12 weeks and not the last, you would not have taken the additional 14 weeks of leave, this would in my opinion fall under Ragsdale.