Any revisions to the May 1, 2013 499Q
Other than an appeal to USAC or the FCC (which generally aren't successful), the only way to correct an error after the 45 day revision deadline is through next year's April 1st 499A, when you file actual 2013 revenues. Keep in mind that the 499A true up methodology includes an implicit penalty for over or under projections made on the 499Qs. Bottom line -- be as accurate as possible when filing projected revenues on the 499Q and fix any errors within the 45 day revision period.