Generally a new TIL disclosure is needed when you are doing a refinance ( a new note), but not when you are doing a modification (an extension/modification agreement. But some examiners demand a new disclosure on a modification when the modification are extensive, such as increasing the APR in addition to extending the maturity date. The safe answer is to give the new disclosure. While the argument for not giving the new disclosure is winnable, do you really want to get into an argument with the examiner.
