You never have to redisclose your preliminary estimated disclsoures unless you change products such as going from a fixed rate to an ARM.
The final TIL is only required if your preliminary disclosures are within the allowable tolerances. However, in today's software world most closing packets will include a final TIL.
From the Official Staff Commentary
Paragraph 19(a)(2) Redisclosure required.
1. Conditions for redisclosure. Creditors must make new disclosures if the annual percentage rate at consummation differs from the estimate originally disclosed by more than 1/8 of 1 percentage point in regular transactions or ¼ of 1 percentage point in irregular transactions, as defined in footnote 46 of §226.22(a). The creditor must also redisclose if a variable-rate feature is added to the credit terms after the original disclosures have been made. The creditor has the option of redisclosing information under other circumstances, if it wishes to do so.
2. Content of new disclosures. If redisclosure is required, the creditor may provide a complete set of new disclosures, or may redisclose only the terms that vary from those originally disclosed. If the creditor chooses to provide a complete set of new disclosures, the creditor may but need not highlight the new terms, provided that the disclosures comply with the format requirements of §226.17(a). If the creditor chooses to disclose only the new terms, all the new terms must be disclosed. For example, a different annual percentage rate will almost always produce a different finance charge, and often a new schedule of payments; all of these changes would have to be disclosed. If, in addition, unrelated terms such as the amount financed or prepayment penalty vary from those originally disclosed, the accurate terms must be disclosed. However, no new disclosures are required if the only inaccuracies involve estimates other than the annual percentage rate, and no variable-rate feature has been added.
3. Timing. Redisclosures, when necessary, must be given no later than "consummation or settlement." "Consummation" is defined in §226.2(a). "Date of settlement" is defined in Regulation X (24 CFR 3500.2(a)) and is subject to any interpretations issued under RESPA and Regulation X.
4. Basis of disclosures. In some cases, a creditor may delay redisclosure until settlement, which may be at a time later than consummation. If a creditor chooses to redisclose at settlement, disclosures may be based on the terms in effect at settlement, rather than at consummation. For example, in a variable-rate transaction, a creditor may choose to base disclosures on the terms in effect at settlement despite the general rule in the commentary to section 18(f) that variable-rate disclosures should be based on the terms in effect at consummation.
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The opinions expressed are mine and they are not to be taken as legal advice.