There are five levels to the Medicare Appeals Process, and the timing appears to be ample for what is required. Here is the amount of delay involved if you wait until the last minute:
120+180+60+60+60=480 days or 16 months. However, it appears that most if not all cases take much longer than that, particularly as higher levels of appeals are confronted.
There is a detailed write-up by Elissa K. Moore, R. Brent Rawlings, and Jessica L. Smith of McGuireWoods here. Title: “A Primer on RAC Appeals“. Moore also is associated with the Annals of Health Law published at Loyola University Chicago School of Law.